EP1402214A2 - Steam generator heating surface comprising a multitude of approximately parallel heating tubes through which a cooling agent passes - Google Patents

Steam generator heating surface comprising a multitude of approximately parallel heating tubes through which a cooling agent passes

Info

Publication number
EP1402214A2
EP1402214A2 EP02754786A EP02754786A EP1402214A2 EP 1402214 A2 EP1402214 A2 EP 1402214A2 EP 02754786 A EP02754786 A EP 02754786A EP 02754786 A EP02754786 A EP 02754786A EP 1402214 A2 EP1402214 A2 EP 1402214A2
Authority
EP
European Patent Office
Prior art keywords
heating surface
heating
tubes
steam generator
protective sleeves
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP02754786A
Other languages
German (de)
French (fr)
Inventor
Andreas Mengel
Steffen Lysk
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GE Power Systems GmbH
Vattenfall Europe Generation AG and Co KG
Original Assignee
Vattenfall Europe Generation AG and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Vattenfall Europe Generation AG and Co KG filed Critical Vattenfall Europe Generation AG and Co KG
Publication of EP1402214A2 publication Critical patent/EP1402214A2/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28G—CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS
    • F28G5/00—Cleaning by distortion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00—Component parts or details of steam boilers
    • F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/10—Water tubes; Accessories therefor
    • F22B37/107—Protection of water tubes

Definitions

  • the invention relates to a heating surface of a steam generator with numerous heating surface tubes through which a cooling medium flows and which run approximately parallel to one another and which are arranged in the flow channel of the steam generator by means of suspensions.
  • the flue gases that are produced during combustion are loaded with dust and ash. Due to the high temperature of the flue gases (approx. 1000 - 1400 ° C), which is above the melting point of the ash, deposits and caking occur, particularly on heating surfaces in the area near the combustion chamber, which are mainly composed of sintered slag and ash components put together.
  • the mechanical excitation means knockers which can lead to damage to the heating surface tubes, and the inadequate cleaning action in the case of very large heating surface expansions are disadvantageous here.
  • the object of the invention to propose to design heating surfaces of steam generators in such a way that a constant growth of the deposits in the form of slagging of the heating surfaces located in the flow area of the flue gases is prevented and the above-mentioned disadvantages are avoided.
  • the object is achieved in that the heating flat tubes are surrounded by protective sleeves between their suspensions, which lie loosely on the surface of the heating flat tubes, the ends of the protective sleeves have an expansion distance from the suspensions of the heating flat tubes and the material of the protective sleeves compared to the material of the heating flat tubes has higher coefficients of thermal expansion.
  • the protective sleeves axially in several parts, preferably in two parts.
  • the parts of the protective sleeve are z. B. firmly connected by welding.
  • the coefficient of thermal expansion of the material of the protective sleeves should advantageously be 1.5 times higher than the coefficient of heat of the material of the heating flat tubes. It also makes sense to measure the gap between the outer surface of the heating surface tubes and the inner surface of the protective sleeve with up to 1 mm in order to ensure that the protective sleeve expands and, on the other hand, to prevent dust from penetrating.
  • the slag that forms on the heating surface tubes when the steam generator is in operation adheres above all to those heating surface tubes that are particularly close to the combustion chamber of the steam generator.
  • the first heating surface tube bundle, and in particular the heating surface tubes lying at the front in the flow path of the flue gases are particularly badly affected by slag caking.
  • the invention is based on the knowledge that compared to the heating surface tubes, which are cooled by a medium flowing through them (water, steam) and due to the higher coefficient of thermal expansion of the material of the protective sleeves compared to the material of the heating surface tubes, the protective sleeves during operation of the steam generator are much more efficient experienced greater expansion in the axial direction.
  • the protective sleeves expand in the direction of the suspensions.
  • the protective sleeves also cover the area of the heating flat tubes, which remains uncovered as an expansion distance to the suspensions of the heating flat tubes when the protective sleeves are installed.
  • the cleaning effect of the flat heating pipes, ie the flaking off of the slag cakes on the protective sleeves now occurs when the steam generator is taken out of operation or load changes occur with temperature changes of the flue gases.
  • the protective sleeves contract significantly more when cooling than the flat heating pipes. This contraction of the protective sleeve causes the slag cakes to flake off and thus the heating surfaces, which have been provided with the protective sleeves due to the risk of slag caking, to be cleaned off.
  • Fig. 1 - a schematic section of a side view of two superimposed heating surface tube bundles in a steam generator
  • Fig. 2 - a schematic side view of a heating surface tube with a protective sleeve mounted around the heating surface tube
  • Fig. 3 - a schematic section through a heating surface tube with a mounted protective sleeve
  • the heating surfaces of the high-pressure and intermediate-pressure superheaters are suspended from a lignite-dust-fired steam generator by means of a series of suspensions 1 fastened to the ceiling of the steam generator in the flow path of the flue gases 6 which are generated in the steam generator during combustion of the lignite dust (FIG. 1).
  • the lignite dust is blown into the combustion chamber 2 of the steam generator at a height of approximately 30 m and burned.
  • a plurality of heating surface tube bundles 3 are fastened in parallel to the suspensions 1.
  • Each of these heating surface tube bundles 3 is formed from a plurality of heating surface tubes 4 running approximately parallel to one another and represents a superheater heating surface of the steam generator.
  • the heating surface tubes 4 of the heating surface tube bundles 3 are arranged in such a way that the heating surface tubes 4 lying one above the other are in a vertical alignment. All superimposed heating surface tubes 4 of a heating surface tube bundle 3 are also referred to as tube disks.
  • the parallel heating surface tube bundles 3 are attached to the suspensions 1 at a distance of approximately 1 m from one another. The space between the individual heating surface tube bundles 3 forms an alley.
  • the ends of the protective sleeves 7 have an expansion distance 8 from the adjacent suspensions 1.
  • the high temperature resistant material of the protective sleeves 7 is selected so that it has a much higher coefficient of thermal expansion (1.5 times) than the material of the heating surface tube 4.
  • the inner diameter of the protective sleeve 7 corresponds essentially to the outer diameter of the heating surface tube 4, so that the inside of the protective sleeve 7 rests on the surface of the heating surface tube 4 (Fig. 3).
  • the gap formed between the heating surface tube 4 and the protective sleeve 7 is approximately 0-1 mm in size.
  • the length of the protective sleeve 7 is chosen so that the two ends of the protective sleeve 7 are each at an expansion distance 8 from the suspensions 1.
  • the protective sleeve expands in the direction of the suspensions during operation of the steam boiler due to the thermal expansion, so that the heating surface tube between the suspensions is almost completely covered with the protective sleeve.
  • the wall thickness of the protective sleeve (approx. 3 - 5 mm) is selected so that the heat transfer from the flue gas to the medium flowing in the heating surface tubes is not excessively impeded.
  • the heating flat tubes can be equipped with the protective sleeves, on which particularly strong slag caking was found during the operation of the steam generator.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Incineration Of Waste (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Catching Or Destruction (AREA)
  • Financial Or Insurance-Related Operations Such As Payment And Settlement (AREA)
  • Professional, Industrial, Or Sporting Protective Garments (AREA)

Abstract

The invention relates to a heating surface of a steam generator comprising a multitude of approximately parallel heating tubes (4) through which a cooling agent passes. Said heating tubes are arranged in the flow channel of the steam generator by means of mountings (1). The aim of the invention is to embody the heating surfaces of the steam generator in such a way as to prevent the continuous build-up of deposits in the form of slagging, and the disadvantages associated therewith, in the area through which the flue gases pass. To achieve this, the heating surface tubes (4) are surrounded by protective sleeves (7) which rest loosely on the surface of the heating surface tubes between the mountings (1) thereof. The ends of the protective sleeves (7) exhibit an expansion distance (8) to the mountings of the heating surface tubes (4). The heat expansion coefficient of the material forming the protective sleeves is higher than that of the material forming the heating surface tubes (4).

Description

Heizfläche eines Dampferzeugers mit zahlreichen, von einem Kühlmedium durchströmten, etwa parallel zueinander verlaufenden HeizflächenrohrenHeating surface of a steam generator with numerous heating surface tubes through which a cooling medium flows, approximately parallel to one another
Die Erfindung betrifft eine Heizfläche eines Dampferzeugers mit zahlreichen, von einem Kühlmedium durchströmten, etwa parallel zueinander verlaufenden Heizflächenrohren, die im Strömungskanal des Dampferzeugers mittels Aufhängungen angeordnet sind.The invention relates to a heating surface of a steam generator with numerous heating surface tubes through which a cooling medium flows and which run approximately parallel to one another and which are arranged in the flow channel of the steam generator by means of suspensions.
Dampferzeuger von Kraftwerken und Heizwerken sowie Wirbelschichtanlagen und Müllverbrennungsanlagen, welche mit Kohlenstaub und anderen festen Brennstoffen befeuert werdeη, weisen u. a. oberhalb der Brennkammer bzw. nachgeschaltet aus Rohrbündeln gebildete Heizflächen auf, welche von Medien, wie Wasser oder Dampf, durchströmt werden, um die Wärme des in der Brennkammer des Dampferzeugers verbrannten Brennstoffs aufzunehmen und abzutransportieren.Steam generators of power plants and heating plants as well as fluidized bed systems and waste incineration plants, which are fired with coal dust and other solid fuels, have u. a. Above the combustion chamber or downstream of tube bundles formed heating surfaces, which are traversed by media such as water or steam to absorb and remove the heat of the fuel burned in the combustion chamber of the steam generator.
Die Rauchgase, welche bei der Verbrennung entstehen, sind staub- und aschebeladen. Durch die hohe Temperatur, welche die Rauchgase aufweisen (ca. 1000 - 1400 °C), und die über dem Schmelzpunkt der Asche liegt, kommt es insbesondere an Heizflächen im brennkammernahen Bereich zu Ablagerungen und Anbackungen, die sich hauptsächlich aus zusammengesinterten Schlacke- und Aschebestandteilen zusammensetzen.The flue gases that are produced during combustion are loaded with dust and ash. Due to the high temperature of the flue gases (approx. 1000 - 1400 ° C), which is above the melting point of the ash, deposits and caking occur, particularly on heating surfaces in the area near the combustion chamber, which are mainly composed of sintered slag and ash components put together.
Diese Ablagerungen und Anbackungen wachsen mit dem Betrieb des Dampferzeugers, so daß sich sogenannte Schlackebärte an den Rohren der Heizflächen bilden. Die Ablagerungen und Anbackungen führen einerseits zur Verschlechterung des Wärmeüberganges zwischen dem in der Brennkammer strömenden Rauchgas und dem die Wärme abtransportierenden Medium in den Rohren der Heizflächen, andererseits werden die Rohre der Heizflächen gewichtsmäßig stärker belastet, was mit einer nachteiligen höheren Belastung der Tragkonstruktion der Heizflächen verbunden ist. Ebenfalls besteht die Gefahr, daß sich bei einer bestimmten Größe der Schlackestücke diese von dem Rohr der Heizfläche infolge ihres Gewichts lösen, in der Brennkammer herabfallen und durch die Wucht des Aufpralls Beschädigungen an den unter den Heizflächen liegenden Anlagenteilen, wie z. B. Trichterschräge oder Nachbrennroste, auftreten. Mit dem Anwachsen der Schlackeanbackungen ist auch das Problem der Arbeitssicherheit bei Arbeiten in der Brennkammer bei außer Betrieb befindlichem Dampferzeuger verbunden. Befindet sich der Arbeitsort unterhalb des Bereiches der Heizflächen mit starken Schlackeanbackungen, ist eine vorherige Be- seitigung der Schlacke aus Arbeitsschutzgründen unbedingt erforderlich. Dies ist aber mit erhöhten Aufwendungen, z. B. Stellen einer weitläufigen Rüstung, verbunden.These deposits and caking grow with the operation of the steam generator, so that so-called slag whiskers form on the tubes of the heating surfaces. The deposits and caking lead on the one hand to the deterioration of the heat transfer between the flue gas flowing in the combustion chamber and the heat-dissipating medium in the tubes of the heating surfaces, on the other hand, the tubes of the heating surfaces are subjected to greater weight, which is associated with a disadvantageously higher load on the supporting structure of the heating surfaces is. There is also the risk that with a certain size of the slag pieces they will detach from the tube of the heating surface due to their weight, fall down in the combustion chamber and be damaged by the impact of the impact on the parts of the system beneath the heating surfaces, such as, for. B. funnel slope or afterburning grates occur. The problem of occupational safety when working in the combustion chamber when the steam generator is out of operation is associated with the increase in the slag caking. If the place of work is below the area of the heating surfaces with heavy slag caking, prior removal of the slag is essential for occupational safety reasons. But this is with increased expenses, for. B. Make extensive armor connected.
Aus der DE 38 19 941 A1 ist ein Verfahren zum Entfernen von Schlackeanba- ckungen von Rohren eines Dampferzeugers bekannt, wobei jeweils wenigstens ein Rohr mit Hilfe eines Schwingungserregers zu Schwingungen, insbesondere Biegeschwingungen, angeregt wird, wodurch die anhaftenden Schlackeablagerungen von den Rohren abplatzen. Durch eine Einstellung der Schwingfrequenz des Schwingerregers ist es möglich, die Rohre einzeln oder in Gruppen zu Schwingungen anzuregen.From DE 38 19 941 A1, a method for removing slag deposits from pipes of a steam generator is known, wherein at least one pipe is excited to vibrations, in particular bending vibrations, with the aid of a vibration exciter, as a result of which the adhering slag deposits flake off the pipes. By adjusting the vibration frequency of the vibration exciter, it is possible to excite the tubes to vibrate individually or in groups.
Nachteilig dabei ist, daß bei großen Heizflächenausdehnungen nicht alle Bereiche ausreichend abreinigen zu können, da durch Mehrfachhalterungen die Schwingungen unterbrochen werden.The disadvantage here is that in the case of large heating surface expansions, it is not possible to clean all areas sufficiently, since the vibrations are interrupted by multiple brackets.
In der DE 196 30 482 A1 ist ein Wärmetauscher beschrieben, bei welchem die Wärmeaustauschrohre im Bereich ihrer Windungen ortsfest gehalten sind und der Bereich zwischen den Windungen mit einem Klopfrohr in Berührung steht. Hier erzeugen ruckartige Bewegungen des Klopfrohres ebenfalls Schwingungen in den Wärmetauscherrohren. Durch die entstehenden Vibrationen soll eben- falls ein Abplatzen der an den Wärmetauscherrohren anhaftenden Schlacke erreicht werden.DE 196 30 482 A1 describes a heat exchanger in which the heat exchange tubes are held stationary in the area of their turns and the area between the turns is in contact with a knocking tube. Here, jerky movements of the knocking tube also generate vibrations in the heat exchanger tubes. The resulting vibrations should also cause the slag adhering to the heat exchanger tubes to flake off.
Nachteilig dabei sind die mechanischen Anregungsmittel Klopfer, welche zu Beschädigungen an den Heizflächenrohren führen können und die ungenügende Reinigungswirkung bei sehr großen Heizflächenausdehnungen.The mechanical excitation means knockers, which can lead to damage to the heating surface tubes, and the inadequate cleaning action in the case of very large heating surface expansions are disadvantageous here.
Es ist deshalb die Aufgabe der Erfindung vorzuschlagen, Heizflächen von Dampferzeugern so zu gestalten, daß ein ständiges Anwachsen der Ablagerungen in Form der Verschlackungen der im Strömungsbereich der Rauchgase befindlichen Heizflächen verhindert wird und die damit verbundenen o. g. Nachteile vermieden werden. Die Aufgabe wird erfindungsgemäß dadurch gelöst, daß die Heizflachenrohre zwischen ihren Aufhängungen von Schutzhülsen umgeben sind, welche lose auf der Oberfläche der Heizflachenrohre aufliegen, die Enden der Schutzhülsen zu den Aufhängungen der Heizflachenrohre einen Dehnungsabstand aufweisen und das Material der Schutzhülsen gegenüber dem Material der Heizflachenrohre einen höheren Wärmeausdehnungskoeffizienten besitzt.It is therefore the object of the invention to propose to design heating surfaces of steam generators in such a way that a constant growth of the deposits in the form of slagging of the heating surfaces located in the flow area of the flue gases is prevented and the above-mentioned disadvantages are avoided. The object is achieved in that the heating flat tubes are surrounded by protective sleeves between their suspensions, which lie loosely on the surface of the heating flat tubes, the ends of the protective sleeves have an expansion distance from the suspensions of the heating flat tubes and the material of the protective sleeves compared to the material of the heating flat tubes has higher coefficients of thermal expansion.
Vorteilhaft dabei ist es, die Schutzhülsen axial mehrteilig, vorzugsweise zweiteilig, auszuführen. Die Teile der Schutzhülse werden dabei z. B. durch Schweißung fest miteinander verbunden. Der Wärmeausdehnungskoeffizient des Materials der Schutzhülsen sollte vorteilhafterweise um das 1 ,5fache höher sein als der Wärmekoeffizient des Materials der Heizflachenrohre. Weiterhin ist es sinnvoll, den Spalt zwischen der Mantelfläche der Heizflachenrohre und der Innenoberfläche der Schutzhülse mit bis zu 1 mm zu bemessen, um eine Deh- nung der Schutzhülse zu gewährleisten und andererseits ein Eindringen von Staub zu verhindern.It is advantageous here to design the protective sleeves axially in several parts, preferably in two parts. The parts of the protective sleeve are z. B. firmly connected by welding. The coefficient of thermal expansion of the material of the protective sleeves should advantageously be 1.5 times higher than the coefficient of heat of the material of the heating flat tubes. It also makes sense to measure the gap between the outer surface of the heating surface tubes and the inner surface of the protective sleeve with up to 1 mm in order to ensure that the protective sleeve expands and, on the other hand, to prevent dust from penetrating.
Die beim Betrieb des Dampferzeugers entstehende Schlacke an den Heizflächenrohren haftet vor allem an solchen Heizflächenrohren, die der Brennkam- mer des Dampferzeugers besonders nah sind. D. h., das erste Heizflächenrohr- bündel, und dort insbesondere die im Strömungsweg der Rauchgase vorn liegenden, zuerst beströmten Heizflachenrohre, sind besonders stark von Schlackeanbackungen betroffen. Durch die Anbringung der Schutzhülsen um diese Heizflachenrohre setzt sich die Schlacke an den Schutzhülsen fest.The slag that forms on the heating surface tubes when the steam generator is in operation adheres above all to those heating surface tubes that are particularly close to the combustion chamber of the steam generator. In other words, the first heating surface tube bundle, and in particular the heating surface tubes lying at the front in the flow path of the flue gases, are particularly badly affected by slag caking. By attaching the protective sleeves around these flat heating pipes, the slag attaches itself to the protective sleeves.
Der Erfindung liegt die Erkenntnis zugrunde, daß gegenüber der Heizflachenrohre, welche durch ein durch sie hindurchströmendes Medium (Wasser, Dampf) gekühlt werden und aufgrund des höheren Wärmeausdehnungskoeffizienten des Materials der Schutzhülsen gegenüber dem Material der Heizflä- chenrohre die Schutzhülsen beim Betrieb des Dampferzeugers eine viel stärkere Ausdehnung in axialer Richtung erfahren. Die Schutzhülsen dehnen sich in Richtung der Aufhängungen aus. Somit bedecken die Schutzhülsen auch den Bereich der Heizflachenrohre, welcher als Dehnungsabstand zu den Aufhängungen der Heizflachenrohre beim Einbauen der Schutzhülsen unbedeckt geblieben ist. Der Reinigungseffekt der Heizflachenrohre, d. h., das Abplatzen der Schlackeanbackungen an den Schutzhülsen tritt nun ein, wenn der Dampferzeuger außer Betrieb genommen wird oder Lastwechsel mit Temperaturänderungen der Rauchgase erfolgen. Die Schutzhülsen ziehen sich beim Abkühlen wesentlich stärker als die Heizflachenrohre zusammen. Dieses Zusammenziehen der Schutzhülse bewirkt ein Abplatzen der Schlackeanbackungen und somit ein Abreinigen der Heizflächen, die aufgrund der Schlackeanbackungsgefahr mit den Schutzhülsen versehen wurden.The invention is based on the knowledge that compared to the heating surface tubes, which are cooled by a medium flowing through them (water, steam) and due to the higher coefficient of thermal expansion of the material of the protective sleeves compared to the material of the heating surface tubes, the protective sleeves during operation of the steam generator are much more efficient experienced greater expansion in the axial direction. The protective sleeves expand in the direction of the suspensions. Thus, the protective sleeves also cover the area of the heating flat tubes, which remains uncovered as an expansion distance to the suspensions of the heating flat tubes when the protective sleeves are installed. The cleaning effect of the flat heating pipes, ie the flaking off of the slag cakes on the protective sleeves now occurs when the steam generator is taken out of operation or load changes occur with temperature changes of the flue gases. The protective sleeves contract significantly more when cooling than the flat heating pipes. This contraction of the protective sleeve causes the slag cakes to flake off and thus the heating surfaces, which have been provided with the protective sleeves due to the risk of slag caking, to be cleaned off.
An einem Ausführungsbeispiel soll nachfolgend die Erfindung näher erläutert werden. Dabei zeigen die Zeichnungen inThe invention will be explained in more detail below using an exemplary embodiment. The drawings show in
Fig. 1 - einen schematischen Ausschnitt einer Seitenansicht von zwei übereinander angeordneten Heizflächenrohrbündeln in einem DampferzeugerFig. 1 - a schematic section of a side view of two superimposed heating surface tube bundles in a steam generator
Fig. 2 - eine schematische Seitenansicht eines Heizflächenrohres mit einer um das Heizflächenrohr montierten SchutzhülseFig. 2 - a schematic side view of a heating surface tube with a protective sleeve mounted around the heating surface tube
Fig. 3 - einen schematischen Schnitt durch ein Heizflächenrohr mit montierter SchutzhülseFig. 3 - a schematic section through a heating surface tube with a mounted protective sleeve
An einem braunkohlestaubgefeuerten Dampferzeuger sind die Heizflächen der Hochdruck- und Zwischendrucküberhitzer mittels einer Reihe an der Decke des Dampferzeugers befestigten Aufhängungen 1 im Strömungsweg der bei der Verbrennung des Braunkohlenstaubes im Dampferzeuger entstehenden Rauchgase 6 aufgehängt (Fig. 1 ). Der Braunkohlenstaub wird in einer Höhe von ca. 30 m in die Brennkammer 2 des Dampferzeugers eingeblasen und verbrannt. Am strömungsseitigen Ende der Brennkammer 2 in einer Höhe von ca. 100 m sind parallel nebeneinander mehrere Heizflächenrohrbündel 3 an den Aufhän- gungen 1 befestigt. Jedes dieser Heizflächenrohrbündel 3 ist aus mehreren, etwa parallel zueinander verlaufenden Heizflächenrohren 4 gebildet und stellt eine Überhitzerheizfläche des Dampferzeugers dar. Die Heizflachenrohre 4 der Heizflächenrohrbündel 3 sind dabei so angeordnet, daß die übereinanderlie- genden Heizflachenrohre 4 in einer senkrechten Flucht liegen. Sämtliche übereinanderliegende Heizflachenrohre 4 eines Heizflächenrohrbün- dels 3 werden auch als Rohrscheibe bezeichnet. Die parallel nebeneinander liegenden Heizflächenrohrbündel 3 sind mit einem Abstand von ca. 1 m voneinander an den Aufhängungen 1 befestigt. Der Zwischenraum zwischen den einzelnen Heizflächenrohrbündeln 3 bildet eine Gasse. Über einer aus parallel nebeneinander angeordneten Heizflächenrohrbün- dein 3 gebildeten Überhitzerheizfläche sind weitere Überhitzerheizflächen aus Heizflächenrohrbündeln 5 an den Aufhängungen 1 befestigt. An den Heizflächenrohren 4, an denen das vorbeiströmende Rauchgas 6 noch Temperaturen aufweist, welche oberhalb der Ascheerweichungstemperatur liegt (ca. 1000 - 1400 °C), werden erfindungsgemäß Schutzhülsen 7 angebracht. Dabei wird jeweils eine Schutzhülse 7 zwischen zwei Aufhängungen 1 eines Heizflächenrohres 4 befestigt (Fig. 2). Das erfolgt vorteilhafterweise so, daß die Schutzhülsen 7 aus zwei axial geteilten Rohrhälften bestehen, die um das Heizflächenrohr 4 gelegt werden und mittels Verschweißen miteinander verbunden werden. Die Schutzhülsen 7 sind mittig auf den Heizflächenrohren 4 zwischen zwei Aufhängungen 1 montiert. Die Enden der Schutzhülsen 7 weisen zu den benachbarten Aufhängungen 1 einen Dehnungsabstand 8 auf. Das hochtemperaturbeständige Material der Schutzhülsen 7 ist dabei so ausgewählt, daß es einen viel höheren Wärmeausdehnungskoeffizienten aufweist (1 ,5fach) als das Material des Heizflächenrohres 4. Der Innendurchmesser der Schutzhülse 7 entspricht im wesentlichen dem Außendurchmesser des Heizflächenrohres 4, so daß die Innenseite der Schutzhülse 7 auf der Oberfläche des Heizflächenrohres 4 aufliegt (Fig. 3). Der zwischen Heizflächenrohr 4 und Schutzhülse 7 gebildete Spalt ist ca. 0 - 1 mm groß. Die Länge der Schutzhülse 7 ist dabei so gewählt, daß die beiden Enden der Schutzhülse 7 zu den Auf- hängungen 1 jeweils einen Dehnungsabstand 8 aufweisen.The heating surfaces of the high-pressure and intermediate-pressure superheaters are suspended from a lignite-dust-fired steam generator by means of a series of suspensions 1 fastened to the ceiling of the steam generator in the flow path of the flue gases 6 which are generated in the steam generator during combustion of the lignite dust (FIG. 1). The lignite dust is blown into the combustion chamber 2 of the steam generator at a height of approximately 30 m and burned. At the flow-side end of the combustion chamber 2 at a height of approx. 100 m, a plurality of heating surface tube bundles 3 are fastened in parallel to the suspensions 1. Each of these heating surface tube bundles 3 is formed from a plurality of heating surface tubes 4 running approximately parallel to one another and represents a superheater heating surface of the steam generator. The heating surface tubes 4 of the heating surface tube bundles 3 are arranged in such a way that the heating surface tubes 4 lying one above the other are in a vertical alignment. All superimposed heating surface tubes 4 of a heating surface tube bundle 3 are also referred to as tube disks. The parallel heating surface tube bundles 3 are attached to the suspensions 1 at a distance of approximately 1 m from one another. The space between the individual heating surface tube bundles 3 forms an alley. Over a superheater heating surface formed from heating surface tube bundles 3 arranged in parallel next to one another, further superheater heating surfaces made of heating surface tube bundles 5 are fastened to the suspensions 1. Protective sleeves 7 are attached to the heating surface tubes 4, at which the flue gas 6 flowing past still has temperatures which are above the ash softening temperature (approx. 1000-1400 ° C.). In this case, a protective sleeve 7 is fastened between two suspensions 1 of a heating surface tube 4 (FIG. 2). This is advantageously done so that the protective sleeves 7 consist of two axially divided tube halves, which are placed around the heating surface tube 4 and are connected to one another by means of welding. The protective sleeves 7 are mounted centrally on the heating surface tubes 4 between two suspensions 1. The ends of the protective sleeves 7 have an expansion distance 8 from the adjacent suspensions 1. The high temperature resistant material of the protective sleeves 7 is selected so that it has a much higher coefficient of thermal expansion (1.5 times) than the material of the heating surface tube 4. The inner diameter of the protective sleeve 7 corresponds essentially to the outer diameter of the heating surface tube 4, so that the inside of the protective sleeve 7 rests on the surface of the heating surface tube 4 (Fig. 3). The gap formed between the heating surface tube 4 and the protective sleeve 7 is approximately 0-1 mm in size. The length of the protective sleeve 7 is chosen so that the two ends of the protective sleeve 7 are each at an expansion distance 8 from the suspensions 1.
Um dieses beidseitig nicht bedeckte Stück des Heizflächenrohres bei Montage der Schutzhülse dehnt sich bei Betrieb des Dampfkessels aufgrund der Wärmedehnung die Schutzhülse in Richtung der Aufhängungen aus, so daß das Heizflächenrohr jeweils zwischen den Aufhängungen nahezu komplett mit der Schutzhülse abgedeckt ist. Die Wandstärke der Schutzhülse (ca. 3 - 5 mm) wird so gewählt, daß der Wärmeübergang vom Rauchgas auf das in den Heizflächenrohren strömende Medium nicht zu stark behindert wird. An den Schutzhülsen setzen sich nunmehr bei Betrieb des Dampferzeugers Schlackeanbackungen an und wachsen je nach Beaufschlagung mit dem heißen Rauchgas zu einer bestimmten Größe. Bei Außerbetriebnahme bzw. bei großen Laständerungen des Dampferzeugers mit der sich daraus ergebenden Abkühlung der Heizflächen ziehen sich aufgrund des Materials der Schutzhülsen mit dem höheren Wärmeausdehnungskoeffizienten diese stärker zusammen als die Heizflachenrohre selbst. Das Zusammenziehen der Schutzhülsen bewirkt nun ein Abplatzen der Schlackeanbackungen von den Schutzhülsen. Damit tritt ein entsprechender Reinigungseffekt der Heizflächen des Dampferzeugers ein.Around this piece of the heating surface tube, which is not covered on both sides, when the protective sleeve is installed, the protective sleeve expands in the direction of the suspensions during operation of the steam boiler due to the thermal expansion, so that the heating surface tube between the suspensions is almost completely covered with the protective sleeve. The wall thickness of the protective sleeve (approx. 3 - 5 mm) is selected so that the heat transfer from the flue gas to the medium flowing in the heating surface tubes is not excessively impeded. When the steam generator is in operation, slag caked on the protective sleeves and grows to a certain size depending on the exposure to the hot flue gas. When the steam generator is decommissioned or there are large changes in load with the resulting cooling of the heating surfaces, the material of the protective sleeves with the higher thermal expansion coefficient causes them to contract more than the heating flat tubes themselves. The contraction of the protective sleeves now causes the slag cakes to flake off the protective sleeves. A corresponding cleaning effect of the heating surfaces of the steam generator thus occurs.
Um den Aufwand des Anbringens von Schutzrohren zu minimieren, können auch nur die Heizflachenrohre mit den Schutzhülsen ausgestattet werden, an denen im Betrieb des Dampferzeugers besonders starke Schlackeanbackungen festgestellt wurden.In order to minimize the effort of attaching protective tubes, only the heating flat tubes can be equipped with the protective sleeves, on which particularly strong slag caking was found during the operation of the steam generator.
Durch die Erfindung werden folgende Vorteile erreicht:The following advantages are achieved by the invention:
1 . Kontinuierliche Abreinigung von Heizflächenbereichen während des Betriebes bzw. bei Außerbetriebnahmen.1 . Continuous cleaning of heating surface areas during operation or when decommissioning.
2. Minimierung des Reinigungsaufwandes nach Außerbetriebnahme in Vorbereitung von Befahrungen, Befundaufnahmen und Reparaturen.2. Minimization of the cleaning effort after decommissioning in preparation of visits, findings and repairs.
3. Keine zusätzlichen technischen Einrichtungen zur Abreinigung erforderlich wie Klopfeinrichtungen, Schwingungserreger u. a.3. No additional technical facilities for cleaning such as knocking devices, vibration exciters u. a.
4. Minimierung der Belagstärke auf dem Heizflächenrohr, damit Verbesserung des Wärmeüberganges unter Berücksichtigung des Schutzrohres. 4. Minimization of the covering thickness on the heating surface tube, thus improving the heat transfer while taking into account the protective tube.
Aufstellung der verwendeten BezugszeichenList of the reference symbols used
1 Aufhängung1 suspension
2 Brennkammer 3 Heizflächenrohrbündel2 combustion chamber 3 heating surface tube bundle
4 Heizflächenrohr4 heating surface tube
5 Heizflächenrohrbündel5 heating surface tube bundles
6 Rauchgas6 flue gas
7 Schutzhülse 8 Dehnungsabstand 7 protective sleeve 8 expansion distance

Claims

Patentansprüche claims
1. Heizfläche eines Dampferzeugers mit zahlreichen, von einem Kühlmedium durchströmten, etwa parallel zueinander verlaufenden Heizflächenrohren, die im Strömungskanal des Dampferzeugers mittels Aufhängungen angeordnet sind, g e k e n n z e i c h n e t d a d u r c h, daß die Heizflachenrohre (4) zwischen ihren Aufhängungen (1 ) von Schutzhülsen (7) umgeben sind, welche lose auf der Oberfläche der Heizflachenrohre (4) aufliegen, die Enden der Schutzhülsen (7) zu den Aufhängungen (1 ) der Heizflachenrohre (4) einen Dehnungsabstand (8) aufweisen und das Material der Schutzhülsen (7) gegenüber dem Material der Heizflachenrohre (4) einen höheren Wärmeausdehnungskoeffizienten besitzt.1.Heating surface of a steam generator with numerous heating surface tubes through which a cooling medium flows, approximately parallel to one another and which are arranged in the flow channel of the steam generator by means of suspensions, characterized in that the heating surface tubes (4) are surrounded by protective sleeves (7) between their suspensions (1) , which lie loosely on the surface of the heating flat tubes (4), the ends of the protective sleeves (7) from the suspensions (1) of the heating flat tubes (4) have an expansion distance (8) and the material of the protective sleeves (7) compared to the material of the heating flat tubes (4) has a higher coefficient of thermal expansion.
2. Heizfläche nach Anspruch 1 , gekennzeichnet dadurch, daß die Schutzhülsen (7) axial mehrteilig, vorzugsweise zweiteilig, ausgeführt sind, wobei die Teile der Schutzhülsen (7) miteinander fest verbunden sind.2. Heating surface according to claim 1, characterized in that the protective sleeves (7) are made axially in several parts, preferably in two parts, the parts of the protective sleeves (7) being firmly connected to one another.
3. Heizfläche nach Anspruch 1 oder 2, gekennzeichnet dadurch, daß das Mate- rial der Schutzhülsen (7) gegenüber dem Material der Heizflachenrohre (4) mindestens einen 1 ,5fach höheren Wärmeausdehnungskoeffizienten besitzt.3. Heating surface according to claim 1 or 2, characterized in that the material of the protective sleeves (7) compared to the material of the heating surface tubes (4) has at least a 1.5 times higher thermal expansion coefficient.
4. Heizfläche nach einem oder mehreren der Ansprüche 1 bis 3, gekennzeichnet dadurch, daß der Spalt zwischen der Mantelfläche der Heizflachenrohre (4) und der Innenoberfläche der Schutzhülsen (7) bis zu 1 mm groß ist.4. Heating surface according to one or more of claims 1 to 3, characterized in that the gap between the outer surface of the heating surface tubes (4) and the inner surface of the protective sleeves (7) is up to 1 mm.
Hierzu 3 Seiten Zeichnungen 3 pages of drawings
EP02754786A 2001-07-02 2002-06-27 Steam generator heating surface comprising a multitude of approximately parallel heating tubes through which a cooling agent passes Pending EP1402214A2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10131524 2001-07-02
DE2001131524 DE10131524B4 (en) 2001-07-02 2001-07-02 Heating surface of a steam generator with numerous heating surface tubes through which a cooling medium flows and which run approximately parallel to one another
PCT/EP2002/007144 WO2003004934A2 (en) 2001-07-02 2002-06-27 Steam generator heating surface comprising a multitude of approximately parallel heating tubes through which a cooling agent passes

Publications (1)

Publication Number Publication Date
EP1402214A2 true EP1402214A2 (en) 2004-03-31

Family

ID=7689998

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02754786A Pending EP1402214A2 (en) 2001-07-02 2002-06-27 Steam generator heating surface comprising a multitude of approximately parallel heating tubes through which a cooling agent passes

Country Status (5)

Country Link
EP (1) EP1402214A2 (en)
CN (1) CN1231698C (en)
AU (1) AU2002321138B9 (en)
DE (1) DE10131524B4 (en)
WO (1) WO2003004934A2 (en)

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CN106196001A (en) * 2016-08-30 2016-12-07 江苏汇能锅炉有限公司 The vertical convection superheater of medium-pressure boiler
CN106196000A (en) * 2016-08-30 2016-12-07 江苏汇能锅炉有限公司 Low temperature vertical convection superheater for boiler

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FI122481B (en) * 2004-12-29 2012-02-15 Metso Power Oy Superheater design

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Publication number Priority date Publication date Assignee Title
CN106196001A (en) * 2016-08-30 2016-12-07 江苏汇能锅炉有限公司 The vertical convection superheater of medium-pressure boiler
CN106196000A (en) * 2016-08-30 2016-12-07 江苏汇能锅炉有限公司 Low temperature vertical convection superheater for boiler
CN106196001B (en) * 2016-08-30 2019-02-12 江苏汇能锅炉有限公司 The vertical convection superheater of medium-pressure boiler
CN106196000B (en) * 2016-08-30 2019-03-05 江苏汇能锅炉有限公司 Low temperature vertical convection superheater for boiler

Also Published As

Publication number Publication date
DE10131524A1 (en) 2003-01-23
CN1231698C (en) 2005-12-14
WO2003004934A2 (en) 2003-01-16
CN1522351A (en) 2004-08-18
AU2002321138B9 (en) 2005-07-28
WO2003004934A3 (en) 2003-11-27
AU2002321138B2 (en) 2005-07-21
DE10131524B4 (en) 2004-04-15

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