EP0362551B1 - Process and system to sustain a constant temperature in a fluidised-bed combustion plant - Google Patents

Process and system to sustain a constant temperature in a fluidised-bed combustion plant Download PDF

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Publication number
EP0362551B1
EP0362551B1 EP89115969A EP89115969A EP0362551B1 EP 0362551 B1 EP0362551 B1 EP 0362551B1 EP 89115969 A EP89115969 A EP 89115969A EP 89115969 A EP89115969 A EP 89115969A EP 0362551 B1 EP0362551 B1 EP 0362551B1
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EP
European Patent Office
Prior art keywords
bed
temperature
bed temperature
fluidised
solid matter
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EP89115969A
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German (de)
French (fr)
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EP0362551A2 (en
EP0362551A3 (en
Inventor
Helmuth Huschauer
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Deutsche Babcock Werke Energie und Umwelttechnik AG
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Deutsche Babcock Werke Energie und Umwelttechnik AG
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Priority to AT89115969T priority Critical patent/ATE89906T1/en
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Publication of EP0362551A3 publication Critical patent/EP0362551A3/en
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    • 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
    • F22B31/0084—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 with recirculation of separated solids or with cooling of the bed particles outside the combustion bed
    • 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
    • F23C10/005—Fluidised bed combustion apparatus comprising two or more beds
    • 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
    • F23C10/02—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed
    • F23C10/04—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone
    • F23C10/08—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases
    • F23C10/10—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases the separation apparatus being located outside the combustion chamber
    • 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
    • F23C10/18—Details; Accessories
    • F23C10/28—Control devices specially adapted for fluidised bed, combustion apparatus
    • F23C10/30—Control devices specially adapted for fluidised bed, combustion apparatus for controlling the level of the bed or the amount of material in the bed
    • F23C10/32—Control devices specially adapted for fluidised bed, combustion apparatus for controlling the level of the bed or the amount of material in the bed by controlling the rate of recirculation of particles separated from the flue gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N1/00—Regulating fuel supply
    • F23N1/02—Regulating fuel supply conjointly with air supply
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2225/00—Measuring
    • F23N2225/08—Measuring temperature
    • F23N2225/16—Measuring temperature burner temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2237/00—Controlling
    • F23N2237/18—Controlling fluidized bed burners

Definitions

  • the invention relates to a method and a device for maintaining a constant bed temperature in a fluidized bed combustion system with the features of the preamble of claims 1 and 2.
  • a fluidized bed combustion system is known from document EP-A-0 093 063.
  • a fluidized bed firing of the generic type is also known, for example, from "Technical Bulletins" 1984, pages 298 to 300.
  • a change in load is brought about by a simultaneous change in the fuel and air mass flow.
  • the change in the fuel mass flow has a direct influence on the bed temperature.
  • the heating surface sections following the fluidized bed and the free space in the flue gas flow are influenced in their heat output by the change in bed temperature over time and by the change in the flue gas mass flow in their heat output.
  • the bed temperature can fluctuate within certain limits, for example due to a different burnout, even when the steam generator is under the same load.
  • a constant bed temperature is desirable for procedural and combustion reasons, in particular for emission reasons.
  • the flue gas and the solids contained in it are cooled by convection heating surfaces.
  • the separated and cooled solids lower the bed temperature.
  • the bed temperature can thus be influenced by the amount of solids returned to the fluidized bed.
  • the invention has for its object to keep the bed temperature constant with simple means in a fluidized bed combustion with a low expanded fluidized bed and a return of colder solids.
  • the amount of solid discharged from the siphon very precisely follows the amount of fluidizing gas above the loosening rate.
  • the amount of fluidizing gas is therefore used as a manipulated variable which compensates for changes in the controlled variable.
  • the invention is particularly suitable for keeping the bed temperature constant. An influence by different temperatures of the solid has no influence on the bed temperature.
  • the fluidized bed firing is used to heat a steam generator, of which the first boiler train 1 is shown.
  • This first boiler train 1 is followed by one or more boiler trains in which secondary heating surfaces are arranged.
  • the first boiler train 1 consists entirely of gas-tight welded tube walls that work as an evaporator.
  • the boiler train 1 is constructed from the bottom upwards from an air box 3 under a nozzle base 4, a stationary, low-expanded fluidized bed 5 and a free space 6 above the fluidized bed 5.
  • Fluidized bed 5 and free space 6 represent the combustion chamber of the fluidized bed furnace.
  • the fluidizing speed is 3 to 5 m / s so high that medium-sized particles (about 0.5 mm) are also discharged from the fluidized bed 5.
  • Convection heating surfaces 7 with superheater, economizer and evaporator tubes are arranged above the free space 6.
  • the flue gas temperature at the upper end of the boiler train 1 is between 300 and 500 degrees C, depending on the application. At this temperature, the flue gas enters the cyclone separator 8, of which only one is shown in FIG. 1.
  • the cyclone separators 8 separate the solids carried by the flue gas, which is returned to the fluidized bed 5 and cools it.
  • Pre-heated air is supplied via a line 9 and divided into primary air and secondary air.
  • the primary air fed into the air box 3 fluidizes the fluidized bed 5 after passing through the nozzle base 4.
  • the secondary air penetrates into the free space 6 above the fluidized bed 5 via nozzles, preferably on two levels.
  • Raw coal is used as fuel, which is broken down to a maximum grain size and temporarily stored in one or more bunkers 10. 1, the coal is withdrawn from the bunker 10 via a feeder 11 and fed onto the fluidized bed 5 within the tank train 1 via a throwing feeder or together with the solid separated in the cyclone separator 8.
  • Limestone for desulfurization is stored in a bunker 12 and metered into the fluidized bed 5 from below via a conveyor system 13.
  • a standpipe 14 is connected to the solids discharge of the cyclone separator 8 and opens into a siphon 15 from above.
  • the separated solid builds up in the standpipe 14 and thus causes a seal.
  • the standpipe 14 also takes on the task of storing solids so that the siphon 15 has a sufficiently large amount of solids for bed cooling when the load increases rapidly.
  • an overflow 16 is provided, by means of which the maximum fill level in the standpipe 14 is limited.
  • the siphon 15 consists of a swirl chamber 17 which is separated from an air chamber 19 by a nozzle base 18.
  • a supply line 20 is connected to the air chamber 19, through which air is conveyed into the air chamber 19 by means of a blower 21.
  • the introduced air fluidizes the solid located within the swirl chamber 17.
  • a drop chute 22 is connected to the upper part of the swirl chamber 17 and opens into the boiler train 1 in the region of the fluidized bed 5.
  • the fluidized solid flows via the chute 22 onto the fluidized bed 5, as a result of which the solid accumulated in the standpipe 14 flows into the swirl chamber 17 of the siphon 15.
  • the amount of the flowing solid depends on the amount of air supplied to the siphon 15.
  • another gaseous medium for example flue gas, can be used for fluidization.
  • the amount of fluidizing air fed into the siphon 15 is controlled by a control element 24 provided with a servomotor 23 and measured through a measuring orifice 25.
  • Control element 24 and orifice plate 25 are arranged in the feed line 20. (See also FIG. 2)
  • a trim flap 26 is connected upstream of the regulating member 24 is set that with the arrangement of several cyclone separators 8 and siphons 15, the system is evenly charged with air.
  • a temperature sensor 27 for detecting the bed temperature is arranged in the fluidized bed 5.
  • the temperature sensor 27 is connected via an electrical line 28 to a controller 29 which controls the servomotor 23 of the control element 24.
  • the bed temperature is kept constant at various loads of the fluidized bed 5 via this control loop, the amount of air supplied to the siphon 15 being the manipulated variable. If the bed temperature measured with the aid of the temperature sensor 27 exceeds a predetermined value, then the controller 29 causes the control element 24 to open further, so that the flow of solids entering the fluidized bed 5 is increased via the now increased air flow. The returned colder solid cools the fluidized bed 5 so that the bed temperature drops to the predetermined value. If the bed temperature falls below the predetermined value, the control element 24 throttles the amount of air in an analogous manner, as a result of which the amount of solids introduced into the fluidized bed 5 is reduced. The bed temperature adapts to the specified value through less cooling.

Abstract

To maintain a constant regulating variable, particularly of the bed temperature of a fluidized-bed combustion plant, a regulating element (24) is used which is arranged in a feed line (20) for feeding fluidization air to a syphon (15), via which solid matter separated from the flue gas of the fluidized-bed combustion plant is fed back into the fluidized bed (5). The actuating drive (23) of the regulating element (24) is coupled to a temperature sensor (27) arranged in the fluidized bed (5), in such a manner that the quantity of fluidizing air is increased when the measured bed temperature exceeds a predetermined value. The quantity of fluidizing air is reduced when the measured bed temperature drops below the predetermined value. <IMAGE>

Description

Die Erfindung betrifft ein Verfahren und eine Vorrichtung zur Einhaltung einer konstanten Bettemperatur, in einer Wirbelschichtfeuerungsanlage mit den Merkmalen des Oberbegriffs der Ansprüche 1 und 2. Eine solche Wirbelschichtfeuerungsanlage ist aus Dokument EP-A-0 093 063 bekannt.The invention relates to a method and a device for maintaining a constant bed temperature in a fluidized bed combustion system with the features of the preamble of claims 1 and 2. Such a fluidized bed combustion system is known from document EP-A-0 093 063.

Eine Wirbelschichtfeuerung der gattungsgemäßen Art ist zum Beispiel auch aus "Technische Mitteilungen" 1984, Seiten 298 bis 300 bekannt. Bei einer solchen Wirbelschichtfeuerung wird eine Laständerung durch eine gleichzeitige Änderung des Brennstoff- und Luftmassenstroms bewirkt. Durch die Änderung des Brennstoffmassenstromes wird direkt auf die Bettemperatur Einfluß genommen. Die im Rauchgasstrom dem Wirbelbett und dem Freiraum nachfolgenden Heizflächenabschnitte werden in ihrer Wärmeleistung durch die zeitliche Änderung der Bettemperatur und durch die Änderung des Rauchgasmassenstromes in ihrer Wärmeleistung beeinflußt. Die Bettemperatur kann auch bei gleichem Lastzustand des Dampferzeugers zum Beispiel durch einen unterschiedlichen Ausbrand in gewissen Grenzen schwanken. Aus verfahrens- und feuerungstechnischen Gründen, insbesondere aus Gründen der Emission, ist aber eine gleichbleibende Bettemperatur erwünscht.A fluidized bed firing of the generic type is also known, for example, from "Technical Bulletins" 1984, pages 298 to 300. With such a fluidized bed combustion, a change in load is brought about by a simultaneous change in the fuel and air mass flow. The change in the fuel mass flow has a direct influence on the bed temperature. The heating surface sections following the fluidized bed and the free space in the flue gas flow are influenced in their heat output by the change in bed temperature over time and by the change in the flue gas mass flow in their heat output. The bed temperature can fluctuate within certain limits, for example due to a different burnout, even when the steam generator is under the same load. However, a constant bed temperature is desirable for procedural and combustion reasons, in particular for emission reasons.

Es ist bei Wirbelschichtfeuerungen mit einer zirkulierenden Wirbelschicht (VGB Kraftwerkstechnik 67 (1987) Seiten 437 bis 443) bekannt, die im Kreislauf geführten Feststoffe zum Teil in externen Feststoffkühlern zu kühlen und vermischt mit heißen Feststoffen der Wirbelschichtfeuerung zur Bettemperaturregelung zuzuführen. Das geschieht über einen Siphon, der mit Luft zur Fluidisierung des Siphoninhaltes beaufschlagt ist. Dabei wird der Siphon mit einer über dem Lockerungspunkt liegenden konstanten Luftmenge fluidisiert.In fluidized bed furnaces with a circulating fluidized bed (VGB Kraftwerkstechnik 67 (1987) pages 437 to 443), it is known to partially cool the circulated solids in external solid coolers and mixed them with hot solids to supply the fluidized bed firing for bed temperature control. This is done via a siphon, which is supplied with air to fluidize the contents of the siphon. The siphon is fluidized with a constant amount of air above the loosening point.

Bei einer niedrig expandierten Wirbelschicht wird das Rauchgas und die darin enthaltenen Feststoffe durch Konvektionsheizflächen gekühlt. Die abgeschiedenen und gekühlten Feststoffe bewirken eine Absenkung der Bettemperatur. Über die Menge der in das Wirbelbett rückgeführten Feststoffe kann somit die Bettemperatur beeinflußt werden.In the case of a low-expansion fluidized bed, the flue gas and the solids contained in it are cooled by convection heating surfaces. The separated and cooled solids lower the bed temperature. The bed temperature can thus be influenced by the amount of solids returned to the fluidized bed.

Der Erfindung liegt die Aufgabe zugrunde, bei einer Wirbelschichtfeuerung mit einem niedrig expandierten Wirbelbett und einer Rückführung von kälteren Feststoffen die Bettemperatur mit einfachen Mitteln konstant zu halten.The invention has for its object to keep the bed temperature constant with simple means in a fluidized bed combustion with a low expanded fluidized bed and a return of colder solids.

Diese Aufgabe wird erfindungsgemäß durch ein Verfahren gemäß Anspruch 1 und eine Vorrichtung gemäß Anspruch 2 gelöst.This object is achieved according to the invention by a method according to claim 1 and a device according to claim 2.

Es hatte sich gezeigt, daß die aus dem Siphon ausgetragene Menge an Feststoff oberhalb der Lockerungsgeschwindigkeit sehr genau der Fluidisierungsgasmenge folgt. Die Fluidisierungsgasmenge wird daher als Stellgröße verwendet, über die Änderungen der Regelgröße ausgeglichen werden. Die Erfindung eignet sich besonders für die Konstanthaltung der Bettemperatur. Dabei ist ein Einfluß durch unterschiedliche Temperaturen des Feststoffes ohne Einfluß auf die Bettemperatur.It had been shown that the amount of solid discharged from the siphon very precisely follows the amount of fluidizing gas above the loosening rate. The amount of fluidizing gas is therefore used as a manipulated variable which compensates for changes in the controlled variable. The invention is particularly suitable for keeping the bed temperature constant. An influence by different temperatures of the solid has no influence on the bed temperature.

Mehrere Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und werden im folgenden näher erläutert. Es zeigen:

Fig. 1
das Verfahrensschema einer Wirbelschichtfeuerung mit einem niedrig expandierten Wirbelbett, und
Fig. 2
ein Schema für die Regelung der Bettemperatur.
Several embodiments of the invention are shown in the drawing and are explained in more detail below. Show it:
Fig. 1
the process diagram of a fluidized bed combustion with a low expanded fluidized bed, and
Fig. 2
a scheme for the regulation of bed temperature.

Die Wirbelschichtfeuerung dient der Beheizung eines Dampferzeugers, von dem der erste Kesselzug 1 dargestellt ist. An diesen ersten Kesselzug 1 schließt sich ein oder mehrere Kesselzüge an, in denen Nachschaltheizflächen angeordnet sind. Der erste Kesselzug 1 besteht vollständig aus gasdicht verschweißten Rohrwänden, die als Verdampfer arbeiten. Der Kesselzug 1 ist von unten nach oben aus einem Luftkasten 3 unter einem Düsenboden 4, einem stationären, niedrig expandierten Wirbelbett 5 und einen Freiraum 6 oberhalb des Wirbelbettes 5 aufgebaut. Wirbelbett 5 und Freiraum 6 stellen den Feuerraum der Wirbelschichtfeuerung dar. Die Wirbelgeschwindigkeit liegt mit 3 bis 5 m/s so hoch, daß auch Partikel mittlerer Größe (etwa 0,5 mm) aus dem Wirbelbett 5 ausgetragen werden.The fluidized bed firing is used to heat a steam generator, of which the first boiler train 1 is shown. This first boiler train 1 is followed by one or more boiler trains in which secondary heating surfaces are arranged. The first boiler train 1 consists entirely of gas-tight welded tube walls that work as an evaporator. The boiler train 1 is constructed from the bottom upwards from an air box 3 under a nozzle base 4, a stationary, low-expanded fluidized bed 5 and a free space 6 above the fluidized bed 5. Fluidized bed 5 and free space 6 represent the combustion chamber of the fluidized bed furnace. The fluidizing speed is 3 to 5 m / s so high that medium-sized particles (about 0.5 mm) are also discharged from the fluidized bed 5.

Oberhalb des Freiraumes 6 sind Konvektionsheizflächen 7 mit Überhitzer-, Economiser- und Verdampferrohren angeordnet. Die Rauchgastemperatur am oberen Ende des Kesselzuges 1 liegt je nach Anwendungsfall zwischen 300 und 500 Grad C. Mit dieser Temperatur tritt das Rauchgas in Zyklonabscheider 8 ein, von denen in Fig. 1 nur einer gezeigt ist. Die Zyklonabscheider 8 trennen den von den von dem Rauchgas mitgeführten Feststoff ab, der in das Wirbelbett 5 zurückgeführt wird und dieses kühlt.Convection heating surfaces 7 with superheater, economizer and evaporator tubes are arranged above the free space 6. The flue gas temperature at the upper end of the boiler train 1 is between 300 and 500 degrees C, depending on the application. At this temperature, the flue gas enters the cyclone separator 8, of which only one is shown in FIG. 1. The cyclone separators 8 separate the solids carried by the flue gas, which is returned to the fluidized bed 5 and cools it.

Vorgewärmte Luft wird über eine Leitung 9 zugeführt und in Primärluft und Sekundärluft aufgeteilt. Die in den Luftkasten 3 eingespeiste Primärluft fluidisiert nach dem Durchtritt durch den Düsenboden 4 das Wirbelbett 5. Die Sekundärluft dringt über Düsen, vorzugsweise in zwei Ebenen, in den Freiraum 6 oberhalb des Wirbelbettes 5 ein.Pre-heated air is supplied via a line 9 and divided into primary air and secondary air. The primary air fed into the air box 3 fluidizes the fluidized bed 5 after passing through the nozzle base 4. The secondary air penetrates into the free space 6 above the fluidized bed 5 via nozzles, preferably on two levels.

Als Brennstoff wird Rohkohle verwendet, die auf eine maximale Korngröße gebrochen und in einem oder mehreren Bunkern 10 zwischengelagert wird. Gemäß Fig. 1 wird die Kohle aus dem Bunker 10 über einen Zuteiler 11 abgezogen und über Wurfbeschicker oder zusammen mit dem in dem Zyklonabscheider 8 abgetrennten Feststoff auf das Wirbelbett 5 innerhalb des Kesselzuges 1 eingetragen.Raw coal is used as fuel, which is broken down to a maximum grain size and temporarily stored in one or more bunkers 10. 1, the coal is withdrawn from the bunker 10 via a feeder 11 and fed onto the fluidized bed 5 within the tank train 1 via a throwing feeder or together with the solid separated in the cyclone separator 8.

Kalkstein für die Entschwefelung wird in einem Bunker 12 gespeichert und über ein Fördersystem 13 dosiert von unten in das Wirbelbett 5 eingebracht.Limestone for desulfurization is stored in a bunker 12 and metered into the fluidized bed 5 from below via a conveyor system 13.

An den Feststoffaustrag des Zyklonabscheiders 8 ist ein Standrohr 14 angeschlossen, das von oben in einen Siphon 15 mündet. In dem Standrohr 14 staut sich der abgeschiedene Feststoff und bewirkt so eine Abdichtung. Das Standrohr 14 übernimmt weiterhin die Aufgabe einer Feststoffspeicherung, damit dem Siphon 15 bei einer schnellen Laststeigerung eine ausreichend große Feststoffmenge zur Bettkühlung zur Verfügung steht. Am oberen Ende des Standrohres 14 ist ein Überlauf 16 vorgesehen, über den die maximale Füllhöhe im Standrohr 14 begrent wird.A standpipe 14 is connected to the solids discharge of the cyclone separator 8 and opens into a siphon 15 from above. The separated solid builds up in the standpipe 14 and thus causes a seal. The standpipe 14 also takes on the task of storing solids so that the siphon 15 has a sufficiently large amount of solids for bed cooling when the load increases rapidly. At the upper end of the standpipe 14, an overflow 16 is provided, by means of which the maximum fill level in the standpipe 14 is limited.

Der Siphon 15 besteht aus einer Wirbelkammer 17, die durch einen Düsenboden 18 von einer Luftkammer 19 getrennt ist.An die Luftkammer 19 ist eine Zuführungsleitung 20 angeschlossen, durch die mit Hilfe eines Gebläses 21 Luft in die Luftkammer 19 gefördert wird. Die eingebrachte Luft fluidisiert den sich innerhalb der Wirbelkammer 17 befindlichen Feststoff. An den oberen Teil der Wirbelkammer 17 ist eine Fallschurre 22 angeschlossen, die in den Kesselzug 1 im Bereich des Wirbelbettes 5 mündet. Der fluidisierte Feststoff fließt über die Fallschurre 22 auf das Wirbelbett 5, wodurch der in dem Standrohr 14 aufgestaute Feststoff in die Wirbelkammer 17 des Siphons 15 nachfließt. Die Menge des abfließenden Feststoffes ist abhängig von der Menge der dem Siphon 15 zugeführten Luft. Anstelle von Luft kann auch ein anderes gasförmiges Medium zum Beispiel Rauchgas zur Fluidisierung verwendet werden.The siphon 15 consists of a swirl chamber 17 which is separated from an air chamber 19 by a nozzle base 18. A supply line 20 is connected to the air chamber 19, through which air is conveyed into the air chamber 19 by means of a blower 21. The introduced air fluidizes the solid located within the swirl chamber 17. A drop chute 22 is connected to the upper part of the swirl chamber 17 and opens into the boiler train 1 in the region of the fluidized bed 5. The fluidized solid flows via the chute 22 onto the fluidized bed 5, as a result of which the solid accumulated in the standpipe 14 flows into the swirl chamber 17 of the siphon 15. The amount of the flowing solid depends on the amount of air supplied to the siphon 15. Instead of air, another gaseous medium, for example flue gas, can be used for fluidization.

Die in den Siphon 15 eingespeiste Menge an Fluidisierungsluft wird durch ein mit einem Stellmotor 23 versehenes Regelorgan 24 kontrolliert und durch eine Meßblende 25 gemessen. Regelorgan 24 und Meßblende 25 sind in der Zuführungsleitung 20 angeordnet. (siehe dazu Figur 2) Dem Regelorgan 24 ist eine Trimmklappe 26 vorgeschaltet, die so eingestellt ist, daß bei Anordnung von mehreren Zyklonabscheidern 8 und Siphons 15 das System gleichmäßig mit Luft beaufschlagt wird.The amount of fluidizing air fed into the siphon 15 is controlled by a control element 24 provided with a servomotor 23 and measured through a measuring orifice 25. Control element 24 and orifice plate 25 are arranged in the feed line 20. (See also FIG. 2) A trim flap 26 is connected upstream of the regulating member 24 is set that with the arrangement of several cyclone separators 8 and siphons 15, the system is evenly charged with air.

In dem Wirbelbett 5 ist ein Temperaturfühler 27 zur Erfassung der Bettemperatur angeordnet. Der Temperaturfühler 27 ist über eine elektrische Leitung 28 an einen Regler 29 angeschlossen, der den Stellmotor 23 des Regelorgans 24 ansteuert. Über diesen Regelkreis wird die Bettemperatur bei verschiedenen Lasten des Wirbelbettes 5 konstant gehalten, wobei die dem Siphon 15 zugeführte Menge an Luft die Stellgröße darstellt. Übersteigt die mit Hilfe des Temperaturfühlers 27 gemessene Bettemperatur einen vorgegebenen Wert, so wird über den Regler 29 bewirkt, daß das Regelorgan 24 weiter öffnet, so daß über den nunmehr vergrößerten Luftstrom der in das Wirbelbett 5 gelangende Feststoffstrom vergrößert wird. Der rückgeführte kältere Feststoff kühlt das Wirbelbett 5, so daß die Bettemperatur auf den vorgegebenen Wert absinkt. Sinkt die Bettemperatur unter den vorgegebenen Wert, so drosselt in analoger Weise das Regelorgan 24 die Luftmenge, wodurch die in das Wirbelbett 5 eingebrachte Feststoffmenge reduziert wird. Die Bettemperatur gleicht sich durch eine geringere Kühlung dem vorgegebenen Wert an.A temperature sensor 27 for detecting the bed temperature is arranged in the fluidized bed 5. The temperature sensor 27 is connected via an electrical line 28 to a controller 29 which controls the servomotor 23 of the control element 24. The bed temperature is kept constant at various loads of the fluidized bed 5 via this control loop, the amount of air supplied to the siphon 15 being the manipulated variable. If the bed temperature measured with the aid of the temperature sensor 27 exceeds a predetermined value, then the controller 29 causes the control element 24 to open further, so that the flow of solids entering the fluidized bed 5 is increased via the now increased air flow. The returned colder solid cools the fluidized bed 5 so that the bed temperature drops to the predetermined value. If the bed temperature falls below the predetermined value, the control element 24 throttles the amount of air in an analogous manner, as a result of which the amount of solids introduced into the fluidized bed 5 is reduced. The bed temperature adapts to the specified value through less cooling.

Claims (2)

  1. Method for the maintenance of a constant bed temperature in a fluidised bed furnace with a fluidised bed and a feedback into the fluidised bed of solid matter which has been separated from the flue gas and relative to the fluidised bed is colder, in which the bed temperature is measured and the quantity of solid matter fed back is matched to the bed temperature, characterised thereby that the solid matter is fed back by way of a siphon, in which the solid matter is fluidised by a gaseous medium and that the gas quantity fed to the siphon is matched to the bed temperature in such a way that the gas quantity is increased if the measured bed temperature exceeds, a predetermined value and the gas quantity is reduced if the measured bed temperature falls below the predetermined value.
  2. Device for the maintenance of a constant bed temperature in a fluidised bed (5) for the heating of a steam generator with a boiler flue pass (1) which accommodates the fluidised bed furnace and heating surfaces (7) and downstream of which one or more cyclone separators (8) are connected at the flue gas side, wherein the solid matter discharge of the cyclone separator (8) is connected with the fluidised bed furnace by way of a riser pipe (14) with a siphon (15), which is provided with a feed duct (20) for the feed of fluidising gas, characterised thereby that a temperature sensor (27) is arranged in the fluidised bed (5) and a regulating element (24), which is provided with a setting drive (23), is arranged in the feed duct (20) and that the temperature sensor (27) and the setting drive (23) are coupled together in such a manner that the regulating element (24) is opened in the case of rising bed temperature and is closed in the case of falling bed temperature.
EP89115969A 1988-10-01 1989-08-30 Process and system to sustain a constant temperature in a fluidised-bed combustion plant Expired - Lifetime EP0362551B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89115969T ATE89906T1 (en) 1988-10-01 1989-08-30 METHOD AND DEVICE FOR MAINTAINING A CONSTANT TEMPERATURE IN A FLUIDIZED BED COMBUSTION PLANT.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3833489 1988-10-01
DE3833489A DE3833489A1 (en) 1988-10-01 1988-10-01 METHOD AND DEVICE FOR COMPLYING WITH A CONSTANT CONTROL SIZE IN A FLUIDIZED BURNING PLANT

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EP0362551A2 EP0362551A2 (en) 1990-04-11
EP0362551A3 EP0362551A3 (en) 1991-01-02
EP0362551B1 true EP0362551B1 (en) 1993-05-26

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EP89115969A Expired - Lifetime EP0362551B1 (en) 1988-10-01 1989-08-30 Process and system to sustain a constant temperature in a fluidised-bed combustion plant

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EP (1) EP0362551B1 (en)
JP (1) JP2822064B2 (en)
AT (1) ATE89906T1 (en)
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DE (2) DE3833489A1 (en)

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DE4037252A1 (en) * 1990-11-23 1992-05-27 Metallgesellschaft Ag Siphon for line conveying fine granular solids - in which granular fuel is burned in fluidised bed and subsequently sepd. outside of bed
FI89535C (en) * 1991-04-11 1997-07-22 Tampella Power Oy Foerbraenningsanlaeggning
US5394937A (en) * 1993-03-05 1995-03-07 Nieh; Sen Vortex heat exchange method and device
US5392736A (en) * 1993-12-27 1995-02-28 Foster Wheeler Energy Corporation Fludized bed combustion system and process for operating same
SE9601391L (en) * 1996-04-12 1997-10-13 Abb Carbon Ab Procedure for combustion and combustion plant
FI962653A (en) 1996-06-27 1997-12-28 Foster Wheeler Energia Oy A method and apparatus for controlling the transfer of heat from solid particles in a fluidized bed reactor
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FI120556B (en) * 2006-12-11 2009-11-30 Foster Wheeler Energia Oy A method and apparatus for controlling the temperature of a heat-binding fluidized bed reactor
JP5417753B2 (en) * 2008-07-11 2014-02-19 株式会社Ｉｈｉ Circulating fluidized bed gasifier
JP5868839B2 (en) * 2012-12-27 2016-02-24 三菱重工業株式会社 Char discharge pipe
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Also Published As

Publication number Publication date
EP0362551A2 (en) 1990-04-11
DE3833489A1 (en) 1990-04-05
DD284962A5 (en) 1990-11-28
ATE89906T1 (en) 1993-06-15
DE58904476D1 (en) 1993-07-01
EP0362551A3 (en) 1991-01-02
US5003931A (en) 1991-04-02
JP2822064B2 (en) 1998-11-05
JPH02247407A (en) 1990-10-03

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