EP0286845A1 - Method for the combustion of saline brown coal - Google Patents

Method for the combustion of saline brown coal Download PDF

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Publication number
EP0286845A1
EP0286845A1 EP88103982A EP88103982A EP0286845A1 EP 0286845 A1 EP0286845 A1 EP 0286845A1 EP 88103982 A EP88103982 A EP 88103982A EP 88103982 A EP88103982 A EP 88103982A EP 0286845 A1 EP0286845 A1 EP 0286845A1
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Prior art keywords
free space
fluidized bed
ash
flue gas
temperature
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EP88103982A
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German (de)
French (fr)
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EP0286845B1 (en
Inventor
Rudi Derksen
Rainer Dr. Nottenkämper
Hans-Georg Jarmuzewski
Karl-Heinz Maintok
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Deutsche Babcock Werke Energie und Umwelttechnik AG
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Deutsche Babcock Werke AG
Deutsche Babcock Werke Energie und Umwelttechnik AG
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/002—Fluidised bed combustion apparatus for pulverulent solid fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B31/00—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus
    • F22B31/0007—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus with combustion in a fluidized bed
    • F22B31/0015—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus with combustion in a fluidized bed for boilers of the water tube type
    • F22B31/003—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus with combustion in a fluidized bed for boilers of the water tube type with tubes surrounding the bed or with water tube wall partitions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/003—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for pulverulent fuel

Definitions

  • the invention relates to a method for burning lignite, in particular salt-containing lignite with an excessive amount of alkalis according to the preamble of claim 1.
  • Lignites of normal composition can be burned in dust and fluidized bed furnaces from steam generators.
  • the ash of the lignite has an unfavorable ratio of so-called basic constituents such as CaO and MgO to so-called acidic constituents such as SiO2 and Al2O3 in the presence of alkalis, the lignite becomes more difficult to burn, the higher the base / acid ratio and become alkaline (BRAUNKOHLE 1976, No. 6, pp. 206 - 217).
  • These lignites can then only be fired using special constructions or are not considered suitable for firing.
  • As a special construction on dust-fired boilers a low flame temperature by recirculating cold flue gas in question.
  • the invention has for its object to provide a method for burning lignite, in which the most favorable combustion temperature in the fluidized bed and the free space can be set when using normal lignite and which is also suitable for those saline lignites that are not used in conventional steam generators or could only be used to a limited extent.
  • the fluidized bed allows a lower combustion temperature compared to dust firing.
  • the cold flue gas serves in the absence of bundle heating surfaces in the fluidized bed and / or the free space as a heat carrier for receiving the Combustion heat from the fluidized bed and the free space.
  • saline lignite with an increased alkali content it is possible to maintain a temperature so low that the alkalis are only partially evaporated. Maintaining low wall temperatures in the free space prevents deposits that are difficult to remove from sticking to the pipe wall.
  • a selectively adjustable, higher temperature ensures that the gaseous components of the coal and the entrained coal particles escaping from the fluidized bed are burned out. It is achieved by the features of claim 2 that the heating surfaces with a high wall temperature, on which fuel-related saline deposits adhere, are laid in a second flue gas duct. The salt-containing products resulting from the cleaning of the heating surfaces therefore do not get back into the fluidized bed, so that salting is avoided.
  • the features of claim 3 serve to maintain a sufficient amount of bed material for the operation of the fluidized bed without the alkali content accumulating in the fluidized bed.
  • a steam generator used to fire lignite is designed as a multi-pass boiler and has a first flue gas duct 1, a second flue gas duct 2 and a third flue gas duct 3, which are delimited by gas-tight pipe walls through which water and steam flow.
  • the first flue gas duct 1 serves as a combustion chamber and takes up a fluidized bed 4 in the lower part.
  • the fluidized bed 4 is with an outside Ash processing device 5 connected.
  • a constriction 6 can be formed above the fluidized bed 4 by bending, which causes an additional mixing of the flue gases.
  • the interior of the first flue gas flue 1 is kept free of bundle heating surfaces and represents a free space 7.
  • the second and third flue gas flues 2, 3 are connected by a boiler funnel 8, at the lower end of which a discharge device 9 is arranged.
  • a discharge device 9 is arranged in the second and third flue gas flues 2, 3, heating surfaces 10, 11 are arranged, which are connected as superheaters or economizers. Sootblowers are provided for cleaning the heating surfaces 10, 11.
  • saline lignite is preferably fired, the ash of which contains an alkali fraction of more than 2%.
  • This coal is fed via a coal entry 12 into the fluidized bed 4, in which it is burned with the aid of air.
  • the air is fed into the fluidized bed via a fan 13 through an air line 14. All of the air required for the combustion is preferably introduced into the fluidized bed 4. Alternatively, it can also be provided that part of the air is introduced as secondary and tertiary air into the free space 7 above the fluidized bed 4. Such an air division is particularly to be provided when normal brown coal with an increased nitrogen content is used.
  • Cold flue gas with exhaust gas temperature is drawn off from the cold end of the steam generator and fed into the fluidized bed 4 and the free space 7 above the fluidized bed 4 via a recirculation blower 15 and flue gas lines 16.
  • a pressure-increasing fan 17 is used to compensate for the pressure difference within the fluidized bed 4.
  • the cold flue gas partly absorbs the combustion heat generated in the fluidized bed 4 and in the post-combustion zone within the free space 7.
  • the amount and the distribution of the cold flue gas is carried out in such a way that a temperature of at most 780 degrees C. is set in the fluidized bed 4 and in front of the first heating surface 10 in the second flue gas duct 2.
  • the gas temperature is about 850 degrees C.
  • a wall temperature is set which is about 400 degrees C below the softening temperature of the fly ash.
  • the low bed temperature ensures that a large part of the alkalis in the fluidized bed 4 does not evaporate and that the alkali chlorides and sulfates of the coal ash z. B. be bound to lime, which is supplied to the fluidized bed 4 together with the coal or separately therefrom.
  • Prolonged continuous operation with saline lignite leads to a concentration of the salt content and to a uniform grain formation in the fluidized bed, which limits uniform fluidization. For this reason, it is necessary to continuously remove bed ash. For this reason, part of the bed ash is removed from the fluidized bed 4 via an ash line 18, cooled and fed to the ash processing device 5.
  • the ash processing device is provided with an inlet 19 and a mixing device 20.
  • By treating the ash with a solvent in the ash processing device 5 a large part of the ash or the alkalis is dissolved and removed via a drain line 21.
  • the bed material is reactivated to bind the sulfates and chlorides.
  • the reactivated ash is returned to the fluidized bed 4 to maintain the salt-free bed material.
  • the ashes can be returned directly or via the coal entry 12. Part of the processed ash can be removed from the system via a drain line 22.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)
  • Solid-Fuel Combustion (AREA)
  • Solid Fuels And Fuel-Associated Substances (AREA)

Abstract

In particular saline brown coal with a high alkali content is burned with air in a fluidised bed (4). The resulting combustion gas is post-combusted and cooled in a cooled free space (7) above the fluidised bed (4). Via a recycling blower (15) and flue gas pipes (16), cold flue gas is blown into the fluidised bed (4) and the free space (7) in such a manner that, by virtue of the heat transfer to the cold flue gas and the cooling of the walls of the free space (7), a temperature of 780 degrees C maximum is maintained in the fluidised bed (4) and on the gas-side end of the free space (7), a wall temperature below the fusing temperature of the ash is maintained, and in the free space a post-combustion zone with a temperature of 850 degrees C maximum is maintained. <IMAGE>

Description

Die Erfindung betrifft ein Verfahren zum Verfeuern von Braunkohle insb. von salzhaltiger Braunkohle mit überhöhtem Gehalt an Alkalien nach dem Oberbegriff des Anspruches 1.The invention relates to a method for burning lignite, in particular salt-containing lignite with an excessive amount of alkalis according to the preamble of claim 1.

Braunkohlen normaler Zusammensetzung lassen sich in Staubfeuerungen und Wirbelschichtfeuerungen von Dampferzeugern verbrennen. Weist jedoch die Asche der Braunkohle ein ungünstiges Verhältnis von sogenannten basischen Bestandteilen wie CaO und MgO zu sogenannten sauren Bestandteilen wie SiO₂ und Al₂O₃ bei Anwesenheit von Alkalien auf, so werden die Braunkohlen um so schwieriger verfeuerbar, je höher das Basen/Säuren-Verhältnis und der Alkaligehalt werden (BRAUNKOHLE 1976, Nr. 6, S. 206 - 217). Diese Braunkohlen sind dann entweder nur unter Verwendung von Sonderkonstruktionen verfeuerbar oder gelten als für die Verfeuerung nicht geeignet. Als Sonderkonstruktion an staubgefeuerten Kesseln kommt u.a. eine niedrige Flammentemperatur durch Rückführung von kaltem Rauchgas in Frage.Lignites of normal composition can be burned in dust and fluidized bed furnaces from steam generators. However, if the ash of the lignite has an unfavorable ratio of so-called basic constituents such as CaO and MgO to so-called acidic constituents such as SiO₂ and Al₂O₃ in the presence of alkalis, the lignite becomes more difficult to burn, the higher the base / acid ratio and Become alkaline (BRAUNKOHLE 1976, No. 6, pp. 206 - 217). These lignites can then only be fired using special constructions or are not considered suitable for firing. As a special construction on dust-fired boilers a low flame temperature by recirculating cold flue gas in question.

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Verfeuerung von Braunkohle zu schaffen, bei dem sich beim Einsatz von normaler Braunkohle die günstigste Verbrennungstemperatur in der Wirbelschicht und dem Freiraum einstellen läßt und welches auch für solche salzhaltigen Braunkohlen geeignet ist, die in konventionellen Dampferzeugern nicht oder nur bedingt einsetzbar waren.The invention has for its object to provide a method for burning lignite, in which the most favorable combustion temperature in the fluidized bed and the free space can be set when using normal lignite and which is also suitable for those saline lignites that are not used in conventional steam generators or could only be used to a limited extent.

Diese Aufgabe wird bei einem gattungsgemäßen Verfahren erfindungsgemäß durch die kennzeichnenden Merkmale des Anspruches 1 gelöst. Vorteilhafte Ausgestaltungen der Erfindung sind in den Unteransprüchen angegeben.This object is achieved according to the invention in a generic method by the characterizing features of claim 1. Advantageous embodiments of the invention are specified in the subclaims.

Die Wirbelschicht läßt im Vergleich zu einer Staubfeuerung eine niedrigere Verbrennungstemperatur zu. Das kalte Rauchgas dient bei der Abwesenheit von Bündelheizflächen in der Wirbelschicht und/oder dem Freiraum als Wärmeträger zur Aufnahme der Verbrennungswärme aus der Wirbelschicht und dem Freiraum. Bei der Verfeuerung von normaler Braunkohle bedeutet das, daß durch die Rauchgasrezirkulation eine Anpassung an die jeweils wirtschaftlichste und aus kohlespezifischen Bedingungen erforderliche Verbrennungstemperatur in der Wirbelschicht und dem Freiraum gegeben ist. Bei der Verwendung von salzhaltiger Braunkohle mit einem erhöhten Alkaligehalt kann eine so niedrige Temperatur eingehalten werden, bei der eine Verdampfung der Alkalien nur zum Teil stattfindet. Die Einhaltung niedriger Wandtemperaturen im Freiraum verhindert, daß sich schwer zu entfernende Beläge an der Rohrwand ansetzen. In der Nachverbrennungszone wird durch eine gezielt einstellbare, höhere Temperatur für einen Ausbrand der aus der Wirbelschicht austretenden gasförmigen Bestandteile der Kohle und der mitgerissenen Kohlepartikel gesorgt. Durch die Merkmale des Anspruches 2 wird erreicht, daß die Heizflächen mit hoher Wandtemperatur, auf denen brennstoffbedingt salzhaltige Beläge anhaften, in einen zweiten Rauchgaszug verlegt sind. Die bei der Abreinigung der Heizflächen anfallenden salzhaltigen Produkte gelangen somit nicht wieder in die Wirbelschicht, so daß ein Aufsalzen vermieden wird. Die Merkmale des Anspruches 3 dienen der Aufrechterhaltung einer für einer den Betrieb der Wirbelschicht ausreichenden Menge Bettmaterials, ohne daß sich der Alkaligehalt in der Wirbelschicht anreichert.The fluidized bed allows a lower combustion temperature compared to dust firing. The cold flue gas serves in the absence of bundle heating surfaces in the fluidized bed and / or the free space as a heat carrier for receiving the Combustion heat from the fluidized bed and the free space. When burning normal lignite, this means that the flue gas recirculation adapts to the most economical and necessary combustion temperature in the fluidized bed and the free space. When using saline lignite with an increased alkali content, it is possible to maintain a temperature so low that the alkalis are only partially evaporated. Maintaining low wall temperatures in the free space prevents deposits that are difficult to remove from sticking to the pipe wall. In the afterburning zone, a selectively adjustable, higher temperature ensures that the gaseous components of the coal and the entrained coal particles escaping from the fluidized bed are burned out. It is achieved by the features of claim 2 that the heating surfaces with a high wall temperature, on which fuel-related saline deposits adhere, are laid in a second flue gas duct. The salt-containing products resulting from the cleaning of the heating surfaces therefore do not get back into the fluidized bed, so that salting is avoided. The features of claim 3 serve to maintain a sufficient amount of bed material for the operation of the fluidized bed without the alkali content accumulating in the fluidized bed.

Ein Ausführungsbeispiel der Erfindung wird nachfolgend an der Zeichnung erläutert, die ein Verfahrensschema zur Durchführung der Erfindung darstellt.An embodiment of the invention is explained below with reference to the drawing, which represents a process diagram for implementing the invention.

Ein zur Verfeuerung von Braunkohle dienender Dampferzeuger ist als Mehrzug-Kessel ausgebildet und weist einen ersten Rauchgaszug 1, einen zweiten Rauchgaszug 2 und einen dritten Rauchgaszug 3 auf, die durch von Wasser und Wasserdampf durchströmte, gasdichte Rohrwände begrenzt sind. Der erste Rauchgaszug 1 dient als Brennkammer und nimmt im unteren Teil eine Wirbelschicht 4 auf. Die Wirbelschicht 4 ist mit einer außerhalb liegenden Ascheaufbereitungsvorrichtung 5 verbunden. Oberhalb der Wirbelschicht 4 kann durch Ausbiegungen eine Einschnürung 6 gebildet werden, die eine zusätzliche Vermischung der Rauchgase bewirkt. Der Innenraum des ersten Rauchgaszuges 1 ist frei von Bündelheizflächen gehalten und stellt einen Freiraum 7 dar. Der zweite und dritte Rauchgaszug 2, 3 sind durch einen Kesseltrichter 8 verbunden, an dessen unterem Ende eine Austragsvorrichtung 9 angeordnet ist. In dem zweiten und dem dritten Rauchgaszug 2, 3 sind Heizflächen 10, 11 angeordnet, die als Überhitzer oder Economiser geschaltet sind. Zur Abreinigung der Heizflächen 10, 11 sind Rußbläser vorgesehen.A steam generator used to fire lignite is designed as a multi-pass boiler and has a first flue gas duct 1, a second flue gas duct 2 and a third flue gas duct 3, which are delimited by gas-tight pipe walls through which water and steam flow. The first flue gas duct 1 serves as a combustion chamber and takes up a fluidized bed 4 in the lower part. The fluidized bed 4 is with an outside Ash processing device 5 connected. A constriction 6 can be formed above the fluidized bed 4 by bending, which causes an additional mixing of the flue gases. The interior of the first flue gas flue 1 is kept free of bundle heating surfaces and represents a free space 7. The second and third flue gas flues 2, 3 are connected by a boiler funnel 8, at the lower end of which a discharge device 9 is arranged. In the second and third flue gas flues 2, 3, heating surfaces 10, 11 are arranged, which are connected as superheaters or economizers. Sootblowers are provided for cleaning the heating surfaces 10, 11.

In der Wirbelschicht 4 des beschriebenen Dampferzeugers wird bevorzugt salzhaltige Braunkohle verfeuert, deren Asche einen Alkalianteil von mehr als 2 % enthält. Diese Kohle wird über einen Kohleeintrag 12 in die Wirbelschicht 4 eingespeist, in der sie mit Hilfe von Luft verbrannt wird. Die Luft wird über ein Gebläse 13 durch eine Luftleitung 14 in die Wirbelschicht eingespeist. Bevorzugt wird die gesamte für die Verbrennung notwendige Luft in die Wirbelschicht 4 eingetragen. Alternativ kann auch vorgesehen werden, daß ein Teil der Luft als Sekundär- und Tertiärluft in den Freiraum 7 oberhalb der Wirbelschicht 4 eingebracht wird. Eine solche Lufteinteilung ist besonders dann vorzusehen, wenn normale Braunkohle mit einem erhöhten Stickstoffgehalt zum Einsatz kommt.
Von dem kalten Ende des Dampferzeugers wird kaltes Rauchgas mit Abgastemperatur abgezogen und über ein Rezirkulationsgebläse 15 und Rauchgasleitungen 16 in die Wirbelschicht 4 und den Freiraum 7 oberhalb der Wirbelschicht 4 eingespeist. Zum Ausgleich des Druckunterschiedes innerhalb der Wirbelschicht 4 dient ein Druckerhöhungsgebläse 17. Das kalte Rauchgas nimmt die in der Wirbelschicht 4 und in der Nachverbrennungszone innerhalb des Freiraumes 7 entstehende Verbrennungswärme zum Teil auf. Die Menge und die Aufteilung des kalten Rauchgases erfolgt in der Weise, daß in der Wirbelschicht 4 und vor der ersten Heizfläche 10 in dem zweiten Rauchgaszug 2 eine Temperatur von maximal 780 Grad C eingestellt wird. In der Nachverbrennungszone, in der die aus der Wirbelschicht 4 ausgetragenen Kohlepartikel und die brennbaren Gase nachverbrannt werden, beträgt die Gastemperatur etwa 850 Grad C. Über den Mediumdurchfluß durch die Rohrwände des Freiraumes 7 wird eine Wandtemperatur eingestellt, die mit etwa 400 Grad C unterhalb der Erweichungstemperatur der Flugasche liegt. Durch die niedrige Bettemperatur wird erreicht, daß ein Großteil der Alkalien in der Wirbelschicht 4 nicht verdampft und daß die Alkalichloride und -sulfate der Kohleasche z. B. an Kalk gebunden werden, der zusammen mit der Kohle oder getrennt davon der Wirbelschicht 4 zugeführt wird.In the fluidized bed 4 of the steam generator described, saline lignite is preferably fired, the ash of which contains an alkali fraction of more than 2%. This coal is fed via a coal entry 12 into the fluidized bed 4, in which it is burned with the aid of air. The air is fed into the fluidized bed via a fan 13 through an air line 14. All of the air required for the combustion is preferably introduced into the fluidized bed 4. Alternatively, it can also be provided that part of the air is introduced as secondary and tertiary air into the free space 7 above the fluidized bed 4. Such an air division is particularly to be provided when normal brown coal with an increased nitrogen content is used.
Cold flue gas with exhaust gas temperature is drawn off from the cold end of the steam generator and fed into the fluidized bed 4 and the free space 7 above the fluidized bed 4 via a recirculation blower 15 and flue gas lines 16. A pressure-increasing fan 17 is used to compensate for the pressure difference within the fluidized bed 4. The cold flue gas partly absorbs the combustion heat generated in the fluidized bed 4 and in the post-combustion zone within the free space 7. The amount and the distribution of the cold flue gas is carried out in such a way that a temperature of at most 780 degrees C. is set in the fluidized bed 4 and in front of the first heating surface 10 in the second flue gas duct 2. In the afterburning zone, in which the from the Fluid bed 4 discharged carbon particles and the combustible gases are afterburned, the gas temperature is about 850 degrees C. About the medium flow through the tube walls of the free space 7, a wall temperature is set which is about 400 degrees C below the softening temperature of the fly ash. The low bed temperature ensures that a large part of the alkalis in the fluidized bed 4 does not evaporate and that the alkali chlorides and sulfates of the coal ash z. B. be bound to lime, which is supplied to the fluidized bed 4 together with the coal or separately therefrom.

Ein längerer kontinuierlicher Betrieb mit salzhaltiger Braunkohle führt zu einer Aufkonzentration des Salzgehaltes und zu einer Gleichkornbildung in der Wirbelschicht, wodurch eine gleichmäßige Fluidisierung eingeschränkt wird. Aus diesem Grund ist es erforderlich, kontinuierlich Bettasche abzuziehen. Ein Teil der Bettasche wird aus diesem Grund aus der Wirbelschicht 4 über eine Ascheleitung 18 abgeführt, gekühlt und der Ascheaufbereitungsvorrichtung 5 zugeführt. Die Ascheaufbereitungsvorrichtung ist mit einem Zulauf 19 und einer Mischeinrichtung 20 versehen. Durch die Behandlung der Asche mit einem Lösungsmittel in der Ascheaufbereitungsvorrichtung 5 wird ein großer Teil der Asche bzw. der Alkalien gelöst und über eine Abflußleitung 21 entfernt. Auf diese Weise wird das Bettmaterial zur Bindung der Sulfate und der Chloride reaktiviert. Die reaktivierte Asche wird zur Aufrechterhaltung des salzfreien Bettmaterials in die Wirbelschicht 4 zurückgeführt. Die Rückführung der Asche kann direkt oder über den Kohleeintrag 12 erfolgen. Ein Teil der aufbereiteten Asche kann aus dem System über eine Ablaufleitung 22 entfernt werden.Prolonged continuous operation with saline lignite leads to a concentration of the salt content and to a uniform grain formation in the fluidized bed, which limits uniform fluidization. For this reason, it is necessary to continuously remove bed ash. For this reason, part of the bed ash is removed from the fluidized bed 4 via an ash line 18, cooled and fed to the ash processing device 5. The ash processing device is provided with an inlet 19 and a mixing device 20. By treating the ash with a solvent in the ash processing device 5, a large part of the ash or the alkalis is dissolved and removed via a drain line 21. In this way, the bed material is reactivated to bind the sulfates and chlorides. The reactivated ash is returned to the fluidized bed 4 to maintain the salt-free bed material. The ashes can be returned directly or via the coal entry 12. Part of the processed ash can be removed from the system via a drain line 22.

Claims (3)

1. Verfahren zum Verfeuern von Braunkohle, insb. von salzhaltiger Braunkohle mit erhöhtem Gehalt an Alkalien, zur Dampferzeugung, wobei die Kohle in einer Wirbelschicht mit Luft verbrannt und das entstehende Verbrennungsgas in einem gekühlten Freiraum oberhalb der Wirbelschicht nachverbrannt und gekühlt wird, dadurch gekennzeichnet, daß kaltes Rauchgas in die Wirbelschicht und den Freiraum eingeblasen wird und daß durch die Wärmeabgabe an das kalte Rauchgas und die Kühlung der Wände der Wirbelschicht und des Freiraums in der Wirbelschicht und an dem gasseitigen Ende des Freiraums eine Temperatur von maximal 780 Grad C und eine Wandtemperatur unterhalb der Erweichungstemperatur der Asche sowie in dem Freiraum eine Nachverbrennungszone mit einer Temperatur von maximal 850 Grad C eingehalten werden.1. A process for burning lignite, in particular saline lignite with an increased alkali content, for generating steam, the coal being burned in a fluidized bed with air and the resulting combustion gas being afterburned and cooled in a cooled free space above the fluidized bed, characterized in that that cold flue gas is blown into the fluidized bed and the free space, and that by giving off heat to the cold flue gas and cooling the walls of the fluidized bed and the free space in the fluidized bed and at the gas-side end of the free space, a temperature of at most 780 degrees C and a wall temperature a post-combustion zone with a maximum temperature of 850 degrees C must be maintained below the softening temperature of the ash and in the free space. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß das Verbrennungsgas im Anschluß an den Freiraum in einem oder mehreren Rauchgaszügen mit darin angeordneten Heizflächen gekühlt wird, deren Wandtemperatur oberhalb der Erweichungstemperatur der Asche liegt.2. The method according to claim 1, characterized in that the combustion gas is cooled following the free space in one or more flue gas flues with heating surfaces arranged therein, the wall temperature of which is above the softening temperature of the ash. 3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß ein Teil der Asche aus der Wirbelschicht abgezogen wird, daß die in der Asche enthaltenen Alkalien aus der Asche ausgewaschen werden und daß ein Teil der ausgewaschenen Asche in die Wirbelschicht zurückgeführt wird.3. The method according to claim 1 or 2, characterized in that part of the ash is withdrawn from the fluidized bed, that the alkalis contained in the ash are washed out of the ash and that part of the washed ash is returned to the fluidized bed.
EP88103982A 1987-04-15 1988-03-14 Method for the combustion of saline brown coal Expired - Lifetime EP0286845B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88103982T ATE64190T1 (en) 1987-04-15 1988-03-14 PROCEDURE FOR FIRING INSB. SALINE LIGNITE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3712801 1987-04-15
DE19873712801 DE3712801A1 (en) 1987-04-15 1987-04-15 METHOD FOR BURNING INSB. SALTY BROWN COAL

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EP0286845A1 true EP0286845A1 (en) 1988-10-19
EP0286845B1 EP0286845B1 (en) 1991-06-05

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WO1993005340A1 (en) * 1991-09-12 1993-03-18 Imatran Voima Oy Method and device in the cooling of the circulating material in a fluidized-bed boiler
EP2503239A3 (en) * 2011-03-24 2013-01-23 H S Beratung GmbH & Co. KG Increase of the calorific value range of fuels and the range between minimum and maximum load in fluidized bed combustion
CN104330437A (en) * 2014-10-15 2015-02-04 上海发电设备成套设计研究院 Experiment device for research on coking and contamination prevention of high alkali coal
US10415825B2 (en) * 2016-06-07 2019-09-17 The Babcock & Wilcox Company Methods of generating energy from cellulosic biofuel waste
CN113266844A (en) * 2021-06-08 2021-08-17 南方电网电力科技股份有限公司 Wall temperature deviation control method and device based on opposed firing boiler

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DE3814314C1 (en) * 1988-04-28 1989-06-22 Deutsche Babcock Werke Ag, 4200 Oberhausen, De
DE19855670A1 (en) 1998-12-02 1999-12-09 Siemens Ag Steam generator operating method
DE19903510C2 (en) * 1999-01-29 2002-03-07 Mg Technologies Ag Process for combustion or gasification in the circulating fluidized bed
DE102005035659A1 (en) * 2005-07-29 2007-02-01 Siemens Ag Method for operating boiler of coal fired power plant entails introducing cooling fluid into combustion gas before entry into heat exchanger section to cool combustion gas to temperature below softening temperature of ash particles

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EP0204176A2 (en) * 1985-05-23 1986-12-10 Siemens Aktiengesellschaft Combustion chamber for a fluidized-bed combustor
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993005340A1 (en) * 1991-09-12 1993-03-18 Imatran Voima Oy Method and device in the cooling of the circulating material in a fluidized-bed boiler
US5660148A (en) * 1991-09-12 1997-08-26 Imatran Voima Oy Method and device in the cooling of the circulating material in a fluidized-bed boiler
EP2503239A3 (en) * 2011-03-24 2013-01-23 H S Beratung GmbH & Co. KG Increase of the calorific value range of fuels and the range between minimum and maximum load in fluidized bed combustion
CN104330437A (en) * 2014-10-15 2015-02-04 上海发电设备成套设计研究院 Experiment device for research on coking and contamination prevention of high alkali coal
CN104330437B (en) * 2014-10-15 2017-02-15 上海发电设备成套设计研究院 Experiment device for research on coking and contamination prevention of high alkali coal
US10415825B2 (en) * 2016-06-07 2019-09-17 The Babcock & Wilcox Company Methods of generating energy from cellulosic biofuel waste
CN113266844A (en) * 2021-06-08 2021-08-17 南方电网电力科技股份有限公司 Wall temperature deviation control method and device based on opposed firing boiler
CN113266844B (en) * 2021-06-08 2022-05-27 南方电网电力科技股份有限公司 Wall temperature deviation control method and device based on opposed firing boiler

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DE3712801C2 (en) 1990-04-12
AU594867B2 (en) 1990-03-15
DE3863115D1 (en) 1991-07-11
DD268758A5 (en) 1989-06-07
EP0286845B1 (en) 1991-06-05
DE3712801A1 (en) 1988-11-03
AU1350688A (en) 1988-10-20

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