EP0629273B1 - Flame tube boiler - Google Patents

Flame tube boiler Download PDF

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Publication number
EP0629273B1
EP0629273B1 EP92906303A EP92906303A EP0629273B1 EP 0629273 B1 EP0629273 B1 EP 0629273B1 EP 92906303 A EP92906303 A EP 92906303A EP 92906303 A EP92906303 A EP 92906303A EP 0629273 B1 EP0629273 B1 EP 0629273B1
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EP
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Prior art keywords
tube
fire
flue
blast
fact
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EP92906303A
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German (de)
French (fr)
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EP0629273A1 (en
Inventor
Fritz Dr.-Ing. Schoppe
Josef Dipl.-Ing. PRÖSTLER
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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 
    • F23C3/00—Combustion apparatus characterised by the shape of the combustion chamber
    • 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
    • F22B37/06—Flue or fire tubes; Accessories therefor, e.g. fire-tube inserts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B7/00—Steam boilers of furnace-tube type, i.e. the combustion of fuel being performed inside one or more furnace tubes built-in in the boiler body
    • F22B7/12—Steam boilers of furnace-tube type, i.e. the combustion of fuel being performed inside one or more furnace tubes built-in in the boiler body with auxiliary fire tubes; Arrangement of header boxes providing for return diversion of flue gas flow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J1/00—Removing ash, clinker, or slag from combustion chambers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J3/00—Removing solid residues from passages or chambers beyond the fire, e.g. from flues by soot blowers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/22—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating
    • F24H1/24—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers
    • F24H1/26—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body
    • F24H1/28—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body including one or more furnace or fire tubes
    • F24H1/285—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body including one or more furnace or fire tubes with the fire tubes arranged alongside the combustion chamber

Definitions

  • the present invention relates to a flame tube boiler according to the preamble of claim 1.
  • Such flame tube boilers are generally known. It is a cylindrical, lying boiler drum with one or more flame tubes in it, into which a burner fires at one end. At the other end, the already cooled flue gases leave the flame tube at temperatures of mostly 700 ° C to 1000 ° C and enter a turning chamber, where they are redirected and fed to a flue tube train consisting of a bundle of parallel flue tubes, which are located below the flame tube extend through the boiler drum.
  • the invention has for its object to provide a flame tube boiler of the type mentioned, for firing with dust-like, solid, ash-containing fuels without risk of contamination.
  • the dimensions of the flame tube which are required to maintain the above-mentioned sufficient cooling of the flue gases below the ash softening point, can be calculated from the heat transfer by radiation and convection, taking into account the wall temperature and the laws of fluid mechanics. In this context, reference is made to the VDI Warmth Atlas, from which corresponding information can be found.
  • the number of pipes and their cross sections determine the flow velocity and thus the back pressure of the flue gases in the flue pipes.
  • the total amount of air and the amount of exhaust gas can be calculated from the amount of fuel and the excess air to comply with the TA-Luft regulations. which in turn determines the number and cross-sections of the smoke pipes at a given dynamic pressure.
  • the above-mentioned dynamic pressure is therefore peculiar to each individual boiler.
  • the safety of the boiler according to the invention against contamination by caking of ash constituents at the particularly vulnerable inflow openings of the flue pipes can be further improved if these inflow openings are blown over with a compressed air blast at more or less regular intervals.
  • at least one side wall of the turning chamber is therefore penetrated by at least one blow pipe, the blowing direction of which is directed at least approximately parallel to the partition wall which has the blow pipe inflow openings and separates the turn chamber from the boiler drum, and whose blow cross-section sweeps over all flue pipe inflow openings.
  • This blowpipe is preferably connected via a valve to a gas pressure collector which only has to have a relatively small volume and, for example, stores air under a pressure of 6000 to 8000 hPa.
  • This compressed air creates a pressure surge lasting approximately 0.1 s at intervals of 0.5 to 4 h, which spreads at the speed of sound and sweeps over the entire field of the inflow openings of the flue pipes.
  • the inflow openings of the smoke pipes in the opposite end wall of the turning chamber are opposed by blow pipes, with the aid of which deposits in the region of the inflow openings can be blown away.
  • one or more blowing nozzles are also arranged in the burner-side end wall of the flame tube, through which steam or compressed air can be blown continuously or in bursts into the flame tube in order to remove ash deposits from the flame tube wall.
  • the flame tube boiler consists of an outer boiler drum 1 and one or more cylindrical flame tubes 2 arranged therein. In the example shown in FIGS. 1 and 2, only one flame tube 2 is present. At one end there is an extension 3 for connecting a burner, which is not shown in the present example.
  • This extension 3 can be arranged in or outside the axis of the flame tube 2, wherein the axis of the extension 3 can be parallel or inclined to the axis of the flame tube 2. If the approach 3 for the burner, as shown in Fig. 1, is arranged above the axis of the flame tube 2 and inclined to its axis, so that the burner blows obliquely downwards, then the pulse of the flame gases advantageously blows ash deposits from the bottom of the flame tube 2 away.
  • the flame tube 2 opens at its other end into a turning chamber 4 which is formed by an upper water collector 5, two lower water collectors 6 'and 6 "(FIG. 2) and side walls 7, a bottom wall 23 and a rear end wall 8. These walls are expediently designed as water-cooled membrane walls.
  • a flue pipe train consisting of a plurality of flue pipes 9 running parallel to one another, runs below the flame pipe 2 through the boiler drum 1. These flue pipes 9 have inflow openings on a partition 16 which delimits the boiler drum 1 from the turning chamber 4. At the other end, the smoke pipes open into a flue gas collecting space 18.
  • the two lower water collectors 6 'and 6 "form an opening between them through which ash and other dirt particles can fall down out of the turning chamber 4.
  • the opening opens into a trough 24 in which a screw conveyor 10 is located is located, by means of which the ash parts can be conveyed into an outlet opening 11.
  • one or more blowpipes 12 open into the flame tube 2, through which compressed gas, for example steam or air, can be blown continuously or in pressure surges, in order to blow ash deposits away from there in the direction of the turning chamber .
  • compressed gas for example steam or air
  • blowpipe 13 which extends through one of the side walls 7 of the turning chamber 4, is intended to blow air pressure surges tangentially or at a small angle over the partition 16 in the area where the inflow openings of the smoke pipes 9 are arranged. 4 and 5, the blow pipe 13 is connected via a valve 20 to a pressure collector 21, which is supplied with air pressure by a pressure pump 22.
  • the valve 20, which can be a solenoid valve, the pressure collector 21 and the pump 22 are only shown schematically in FIG. 4.
  • blowpipes 12 Part of the combustion air can be blown in through the blowpipes 12, which has a lower effect on the achievement Levels of CO and NO x affects. Furthermore, these blowpipes can supply steam or compressed air in a constant manner continuously or in bursts.
  • the turning chamber 4 can be seen with a view of the flame tube 2 and the flue tubes 9.
  • the flame tube 2 including a blow tube 12, the water collectors 5, 6 can be seen 'and 6 ".
  • the lower water collectors 6' and 6" are arranged eccentrically and allow the jet effect of the blowpipe 13 when spreading in the known jet angle to record the entirety of the inflow openings of the smoke pipes 9 and deposits that have formed there on the partition 16 could blow away.
  • the bottom wall 23 of the turning chamber 4 is expediently arranged in an inclined manner and leads to the opening already mentioned between the two lower water collectors 6 ′ and 6 ′′ in the mentioned trough 24.
  • FIG. 3 shows a section through the inflow region of one of the smoke pipes 9 on the partition wall 16, which separates the boiler drum 1 from the turning chamber 4.
  • the smoke pipe 9 has an inner radius R and is rounded at the inflow end in a trumpet-like manner with an inner radius of curvature r.
  • the fillet has an axial length of approximately size r.
  • This area is particularly critical with regard to deposits of burning ash particles that are still in a doughy state.
  • these could not entirely follow a deflection which is too sharp as a result of an inner radius of curvature r which is too small, and collar-like precipitation around the inlet into the smoke tube 9 form, which solidify due to the cooling effect of the water-cooled walls and form very hard crusts.
  • Such precipitation is avoided by dimensioning the ratio r: R greater than 0.30, preferably between 0.50 and 0.80, according to the invention.
  • This irregular change in the flue gas velocity in the flue pipes 9 contributes significantly to the formation of collar-like ash incrustations in the area of the inflow openings of the flue pipes 9.
  • the dynamic pressure is preferably in the range between 80 and 200 Pa. Even higher dynamic pressures can lead to dynamic effects (pulsations) of the mass of the smoke gases in the smoke tubes 9 in cooperation with the elasticity and the energy supply of the hot gases in the flame tube 2.
  • blowpipes 17 can be provided in the area of the turning chamber 4, which in particular if there are still oversized particles in the area of the flame tube outlet cross section into the turning chamber, supply this further oxygen for the burnout.
  • These blowpipes 17 can expediently be arranged such that the same oxygen contents are present in all inlet cross sections B of the flue pipes 9.
  • Doors 14 can be arranged on the rear end wall 8 of the turning chamber 4, through which the inflow openings of the smoke tubes 9 and the lower region of the flame tube 2 are accessible.
  • FIG. 4 shows an embodiment of the invention in which two flame tubes 2 are arranged in a boiler drum 1, of which only one is shown in FIG. 4 for reasons of clarity.
  • the other flame tube with associated turning chamber and other components must be imagined to be arranged in mirror image.
  • FIG. 4 shows the end wall cover 14 removed, the field of the inflow openings into the flue pipes 9 and also the blow pipe 13 with valve 20 and pressure collector 21, the blow cross section of the blow pipe 13 being shown in dash-dot lines and, as can be seen, the entire field of the inflow openings of the Smoke pipes 9 sweeps.
  • the direction of flow of the blow pipe 13 is directed essentially obliquely downwards in order to blow away ash deposits which have been blown away into the outlet between the lower water collectors 6 'and 6 ".
  • a feed pipe 25 for additional air can be seen in FIG. 4 under the sloping bottom wall 23 of the turning chamber. which has outlets opening into the turning chamber 4, which are indicated schematically by dash-dotted lines.
  • FIG. 5 shows the arrangement according to FIG. 4 from above, wherein two turning chambers can be seen, which are arranged as a twin arrangement on both sides of the center of the boiler drum 1.
  • the blowpipes 13 is shown with the pressure accumulator 21 attached, this figure essentially showing that the blowpipe 13 blows approximately tangentially over the partition wall 16 which separates the boiler drum 1 from the turning chambers 4.
  • the boiler construction is also suitable for the combustion of liquid, sulfur-containing fuels if a calcareous absorbent, for example hydrated lime, is added to the hot combustion gases in or shortly after the flame.
  • a calcareous absorbent for example hydrated lime
  • exhaust gas temperatures which are lower than the softening temperature of the burnt-out ash particles result at the outlet cross section of the flame tube 2 into the turning chamber 4.
  • particles up to 0.2 to 0.3 mm grain size can burn out in flame tubes. Larger particles enter the turning chamber 4 and the flue pipes 9 in a burning, doughy state a.
  • the softening temperatures of the burnt-out ashes of the different types of coal dust are usually between 950 and 1250 ° C.
  • the boiler is therefore designed to prevent such ash particles from caking in such a way that the flue gases at the outlet from the outlet cross section of the flame tube 2 have a temperature which is a safety distance below the ash softening temperature mentioned.
  • a flue gas collecting space 18 is arranged for extracting the cooled flue gases.
  • This has an access door 19 through which the interior of the flue pipes 9 can be inspected and, in the event of a malfunction, cleaned in the usual way by piercing with long rods, the deposits which have fallen out falling into the trough 24 and being able to be removed by the screw 10.

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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)
  • Gasification And Melting Of Waste (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)
  • Feeding And Controlling Fuel (AREA)
  • Incineration Of Waste (AREA)

Abstract

PCT No. PCT/DE92/00190 Sec. 371 Date Aug. 30, 1994 Sec. 102(e) Date Aug. 30, 1994 PCT Filed Mar. 5, 1992 PCT Pub. No. WO93/18339 PCT Pub. Date Sep. 16, 1993A fire-tube boiler which is suitable for operation with powdered ash-containing fuels and automatically maintains itself clean in operation, has inlet openings, widening in trumpet shape, of flue tubes in the wall which separates the boiler drum from a reversing chamber. The fire tube is so dimensioned that, with due consideration of the boiler capacity, the flue gases at the outlet from the fire tube are cooled by a safety margin to below the ash-softening point of the corresponding fuel. The number and inside diameter of the flue tubes are so dimensioned that a dynamic pressure which is not less than 40 Pa is established in them. A blast tube which blows approximately tangentially over the partition wall is arranged on the reversing chamber in order to keep the inlet openings free of deposits of ash.

Description

Die vorliegende Erfindung bezieht sich auf einen Flammrohrkessel nach dem Oberbegriff des Anspruchs 1.The present invention relates to a flame tube boiler according to the preamble of claim 1.

Solche Flammrohrkessel sind allgemein bekannt. Es handelt sich dabei um eine zylindrische, liegende Kesseltrommel mit einem oder mehreren Flammrohren darin, in die jeweils ein Brenner am einen Ende hineinfeuert. Am anderen Ende verlassen die bereits abgekühlten Rauchgase mit Temperaturen von meist 700°C bis 1000°C das Flammrohr und treten in eine Wendekammer ein, wo sie umgelenkt und einem Rauchrohrzug zugeleitet werden, der aus einem Bündel paralleler Rauchrohre besteht, die sich unterhalb des Flammrohres durch die Kesseltrommel erstrecken.Such flame tube boilers are generally known. It is a cylindrical, lying boiler drum with one or more flame tubes in it, into which a burner fires at one end. At the other end, the already cooled flue gases leave the flame tube at temperatures of mostly 700 ° C to 1000 ° C and enter a turning chamber, where they are redirected and fed to a flue tube train consisting of a bundle of parallel flue tubes, which are located below the flame tube extend through the boiler drum.

Diese Kessel sind für die Befeuerung mit Öl und Gas für die Erzeugung von Dampf, Warmwasser usw. im Einsatz. Sie arbeiten bei Verwendung der vorgenannten Brennstoffe zufriedenstellend.These boilers are used for firing oil and gas for the production of steam, hot water, etc. They work satisfactorily when using the aforementioned fuels.

Bei Befeuerung mit staubförmigen, festen, aschehaltigen Brennstoffen treten bei solchen Flammrohrkesseln jedoch ernste Probleme durch Kesselverschmutzung auf. Da insbesondere größere Brennstoffteilchen während des Verbrennungsvorgangs längere Zeit in teigigem Zustand sind, können sie beim Auftreffen auf kühle Wände dort kleben bleiben, erstarren und Schlackeablagerungen aufbauen, deren Beseitigung Schwierigkeiten macht. In aller Regel muß dazu das Speisewasser aus dem Kessel entleert werden, damit dieser rascher abkühlt, was einen erheblichen Verlust an Speisewasser bedingt und längere Stillstandszeiten zur Folge hat. Mit staubförmigen, aschehaltigen Brennstoffen befeuerte Flammrohrkessel haben sich daher nicht wesentlich durchsetzen können.When fired with dust-like, solid, ash-containing fuels, however, such flame tube boilers pose serious problems due to boiler contamination. Since, in particular, larger fuel particles are in the doughy state for a long time during the combustion process, they can stick to cool walls when they hit them, solidify and build up slag deposits, the elimination of which makes difficulties. As a rule, the feed water must be emptied from the boiler so that it cools down more quickly, which causes a considerable loss of feed water and results in longer downtimes. Flame tube boilers fired with dust-like, ash-containing fuels have therefore not been able to assert themselves significantly.

Der Erfindung liegt die Aufgabe zugrunde, einen Flammrohrkessel der eingangs genannten Art anzugeben, der zur Befeuerung mit staubförmigen, festen, aschehaltigen Brennstoffen ohne Gefahr einer Verschmutzung geeignet ist.The invention has for its object to provide a flame tube boiler of the type mentioned, for firing with dust-like, solid, ash-containing fuels without risk of contamination.

Diese Aufgabe wird durch die kennzeichnenden Merkmale des Anspruchs 1 gelöst. Vorteilhafte Ausgestaltungen der Erfindung sind Gegenstand der Unteransprüche.This object is achieved by the characterizing features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

Zu dem von der Erfindung erreichten Erfolg tragen demgemäß drei Merkmalsgruppen bei:

  • a) die Einströmöffnungen der Rauchrohre sind in bestimmter Weise trompetenartig gestaltet, um dort günstige Strömungsverhältnisse zu erzielen, die Schattenbildungen weitestgehend ausschließen,
  • b) die Abmessungen des Flammrohrs sind derart gewählt, daß die Rauchgase am Austritt aus dem Flammrohr um einen Sicherheitsabstand unter den Ascheerweichungspunkt abgekühlt sind, und
  • c) die Anzahl und die Querschnitte der Rauchrohre sind derart bemessen, daß sich vorbestimmte Staudrücke im zylindrischen Teil des Rohreinlaufs ergeben, die erforderlich sind, um die Ablagerung von Asche in den Rauchrohren zu vermeiden.
Accordingly, three groups of features contribute to the success achieved by the invention:
  • a) the inflow openings of the flue pipes are trumpet-shaped in a certain way in order to achieve favorable flow conditions there, which largely exclude the formation of shadows,
  • b) the dimensions of the flame tube are chosen such that the flue gases at the outlet from the flame tube are cooled by a safety distance below the ash softening point, and
  • c) the number and the cross sections of the flue pipes are dimensioned such that there are predetermined dynamic pressures in the cylindrical part of the pipe inlet, which are necessary to avoid the deposition of ash in the flue pipes.

Die Abmessungen des Flammrohrs, die erforderlich sind, um die genannte ausreichende Abkühlung der Rauchgase unter den Ascheerweichungspunkt zu erhalten, lassen sich aus dem Wärmeübergang durch Strahlung und Konvektion unter Berücksichtigung der Wandtemperatur und der Gesetzmäßigkeiten der Strömungslehre berechnen. In diesem Zusammenhang sei auf den VDI-Wärmeatlas verwiesen, aus dem sich entsprechende Angaben entnehmen lassen. Die Anzahl der Rohre und deren Querschnitte bestimmt bei gegebener Kesselleistung die Strömungsgeschwindigkeit und damit den Staudruck der Rauchgase in den Rauchrohren. Aus der Kesselleistung läßt sich nämlich über die Brennstoffmenge und den Luftüberschuß zur Einhaltung der Bestimmungen der TA-Luft die Gesamtluftmenge und aus dieser die Abgasmenge errechnen, die wiederum bei vorgegebenem Staudruck in den Rauchrohren deren Anzahl und Querschnitte bestimmt. Der vorgenannte Staudruck ist somit jedem individuellen Kessel eigentümlich.The dimensions of the flame tube, which are required to maintain the above-mentioned sufficient cooling of the flue gases below the ash softening point, can be calculated from the heat transfer by radiation and convection, taking into account the wall temperature and the laws of fluid mechanics. In this context, reference is made to the VDI Warmth Atlas, from which corresponding information can be found. For a given boiler output, the number of pipes and their cross sections determine the flow velocity and thus the back pressure of the flue gases in the flue pipes. From the boiler output, the total amount of air and the amount of exhaust gas can be calculated from the amount of fuel and the excess air to comply with the TA-Luft regulations. which in turn determines the number and cross-sections of the smoke pipes at a given dynamic pressure. The above-mentioned dynamic pressure is therefore peculiar to each individual boiler.

Die Sicherheit des erfindungsgemäßen Kessels gegen Verschmutzung durch Anbackungen von Aschebestandteilen an den besonders gefährdeten Einströmöffnungen der Rauchrohre läßt sich noch verbessern, wenn diese Einströmöffnungen in mehr oder weniger regelmäßigen Abständen mit einem Druckluftstoß überblasen werden. In Weiterbildung der Erfindung ist daher wenigstens eine Seitenwand der Wendekammer von wenigstens einem Blasrohr durchdrungen, dessen Blasrichtung wenigstens annähernd parallel zu der die Blasrohreinströmöffnungen aufweisenden Trennwand gerichtet, die die Wendekammer von der Kesseltrommel trennt, und dessen Blasquerschnitt alle Rauchrohreinströmöffnungen überstreicht. Dieses Blasrohr ist vorzugsweise über ein Ventil an einen Gasdrucksammler angeschlossen, der nur ein relativ geringes Volumen aufzuweisen braucht und beispielsweise Luft unter einem Druck von 6000 bis 8000 hPa speichert. Mit dieser Druckluft wird ein Druckstoß von etwa 0,1 s Dauer in Abständen von 0,5 bis 4 h erzeugt, der sich mit Schallgeschwindigkeit ausbreitet und das gesamte Feld der Einströmöffnungen der Rauchrohre überstreicht.The safety of the boiler according to the invention against contamination by caking of ash constituents at the particularly vulnerable inflow openings of the flue pipes can be further improved if these inflow openings are blown over with a compressed air blast at more or less regular intervals. In a further development of the invention, at least one side wall of the turning chamber is therefore penetrated by at least one blow pipe, the blowing direction of which is directed at least approximately parallel to the partition wall which has the blow pipe inflow openings and separates the turn chamber from the boiler drum, and whose blow cross-section sweeps over all flue pipe inflow openings. This blowpipe is preferably connected via a valve to a gas pressure collector which only has to have a relatively small volume and, for example, stores air under a pressure of 6000 to 8000 hPa. This compressed air creates a pressure surge lasting approximately 0.1 s at intervals of 0.5 to 4 h, which spreads at the speed of sound and sweeps over the entire field of the inflow openings of the flue pipes.

Es ist weiterhin vorteilhaft, wenn den Einströmöffnungen der Rauchrohre in der gegenüberliegenden Stirnwand der Wendekammer Blasrohre gegenüberstehen, mit deren Hilfe Ablagerungen im Bereich der Einströmöffnungen weggeblasen werden können. Weiterhin ist es vorteilhaft, wenn auch in der brennerseitigen Stirnwand des Flammrohres ein oder mehrere Blasdüsen angeordnet sind, durch die Dampf oder Druckluft kontinuierlich oder in Stößen in das Flammrohr eingeblasen werden kann, um Ascheablagerungen von der Flammrohrwand zu entfernen.It is furthermore advantageous if the inflow openings of the smoke pipes in the opposite end wall of the turning chamber are opposed by blow pipes, with the aid of which deposits in the region of the inflow openings can be blown away. Furthermore, it is advantageous if one or more blowing nozzles are also arranged in the burner-side end wall of the flame tube, through which steam or compressed air can be blown continuously or in bursts into the flame tube in order to remove ash deposits from the flame tube wall.

Die Erfindung wird nachfolgend unter Bezugnahme auf in den Zeichnungen dargestellte Ausführungsbeispiele näher erläutert. Es zeigt:

Fig. 1
eine Prinzipdarstellung eines Kessels nach der Erfindung (ohne Brenner) im Längsschnitt;
Fig. 2
einen Querschnitt durch die Wendekammer;
Fig. 3
in vergrößerter Darstellung den Einströmöffnungsbereich eines Rauchrohres;
Fig. 4
eine Ausschnittsdarstellung im hinteren Bereich eines Kessels mit zwei Flammrohren von der Stirnseite gesehen, und
Fig. 5
eine Ausschnittsdarstellung im hinteren Bereich des Kessels nach Fig. 4 von oben.
The invention is explained in more detail below with reference to exemplary embodiments shown in the drawings. It shows:
Fig. 1
a schematic diagram of a boiler according to the invention (without burner) in longitudinal section;
Fig. 2
a cross section through the turning chamber;
Fig. 3
in an enlarged view the inflow opening area of a smoke pipe;
Fig. 4
a sectional view in the rear of a boiler with two flame tubes seen from the front, and
Fig. 5
a sectional view in the rear of the boiler of FIG. 4 from above.

Der Flammrohrkessel besteht aus einer äußeren Kesseltrommel 1 und einem oder mehreren darin angeordneten zylindrischen Flammrohren 2. Im in den Figuren 1 und 2 dargestellten Beispiel ist nur ein Flammrohr 2 vorhanden. An dessen einem Ende ist ein Ansatz 3 für den Anschluß eines Brenners ausgebildet, der im vorliegenden Beispiel nicht dargestellt ist. Dieser Ansatz 3 kann in oder außerhalb der Achse des Flammrohrs 2 angeordnet sein, wobei die Achse des Ansatzes 3 parallel oder geneigt zur Achse des Flammrohres 2 sein kann. Wenn der Ansatz 3 für den Brenner, wie in Fig. 1 dargestellt, oberhalb der Achse des Flammrohrs 2 und geneigt zu dessen Achse angeordnet ist, sodaß der Brenner schräg abwärts bläst, dann bläst der Impuls der Flammgase in vorteilhafter Weise Ascheablagerungen vom Boden des Flammrohres 2 weg.The flame tube boiler consists of an outer boiler drum 1 and one or more cylindrical flame tubes 2 arranged therein. In the example shown in FIGS. 1 and 2, only one flame tube 2 is present. At one end there is an extension 3 for connecting a burner, which is not shown in the present example. This extension 3 can be arranged in or outside the axis of the flame tube 2, wherein the axis of the extension 3 can be parallel or inclined to the axis of the flame tube 2. If the approach 3 for the burner, as shown in Fig. 1, is arranged above the axis of the flame tube 2 and inclined to its axis, so that the burner blows obliquely downwards, then the pulse of the flame gases advantageously blows ash deposits from the bottom of the flame tube 2 away.

Das Flammrohr 2 mündet an seinem anderen Ende in eine Wendekammer 4, die von einem oberen Wassersammler 5, zwei unteren Wassersammlern 6' und 6" (Fig. 2) sowie Seitenwänden 7, einer Bodenwand 23 und einer hinteren Stirnwand 8 gebildet ist. Diese Wände sind zweckmäßigerweise als wassergekühlte Membranwände ausgeführt.The flame tube 2 opens at its other end into a turning chamber 4 which is formed by an upper water collector 5, two lower water collectors 6 'and 6 "(FIG. 2) and side walls 7, a bottom wall 23 and a rear end wall 8. These walls are expediently designed as water-cooled membrane walls.

Ein Rauchrohrzug, bestehend aus einer Vielzahl zueinander paralleler Rauchrohre 9 verläuft unterhalb des Flammrohres 2 durch die Kesseltrommel 1. Diese Rauchrohre 9 haben Einströmöffnungen an einer Trennwand 16, die die Kesseltrommel 1 von der Wendekammer 4 abgrenzt. Am anderen Ende münden die Rauchrohre in einen Rauchgassammelraum 18.A flue pipe train, consisting of a plurality of flue pipes 9 running parallel to one another, runs below the flame pipe 2 through the boiler drum 1. These flue pipes 9 have inflow openings on a partition 16 which delimits the boiler drum 1 from the turning chamber 4. At the other end, the smoke pipes open into a flue gas collecting space 18.

Unterhalb der Wendekammer 4 bilden die beiden unteren Wassersammler 6' und 6" zwischen sich eine Öffnung aus, durch die Asche- und andere Schmutzteile nach unten aus der Wendekammer 4 herausfallen können. Die Öffnung mündet in einen Trog 24, in dem sich eine Förderschnecke 10 befindet, mittels der die Ascheteile in eine Austrittsöffnung 11 abgefördert werden können.Below the turning chamber 4, the two lower water collectors 6 'and 6 "form an opening between them through which ash and other dirt particles can fall down out of the turning chamber 4. The opening opens into a trough 24 in which a screw conveyor 10 is located is located, by means of which the ash parts can be conveyed into an outlet opening 11.

Unterhalb des Ansatzes 3 für den Brenner münden in das Flammrohr 2 ein oder mehrere Blasrohre 12, durch die kontinuierlich oder in Druckstößen Druckgas, beispielsweise Dampf oder Luft über die Wände des Flammrohrs 2 geblasen werden kann, um von dort Ascheablagerungen in Richtung auf die Wendekammer fortzublasen.Below the attachment 3 for the burner, one or more blowpipes 12 open into the flame tube 2, through which compressed gas, for example steam or air, can be blown continuously or in pressure surges, in order to blow ash deposits away from there in the direction of the turning chamber .

An weiteres Blasrohr 13, das sich durch eine der Seitenwände 7 der Wendekammer 4 erstreckt, ist dafür vorgesehen, Luftdruckstöße tangential oder unter geringem Winkel über die Trennwand 16 in dem Bereich zu blasen, wo die Einströmöffnungen der Rauchrohre 9 angeordnet sind. Das Blasrohr 13 ist gemäß den Fig. 4 und 5 über ein Ventil 20 mit einem Drucksammler 21 verbunden, der von einer Druckpumpe 22 mit Luftdruck versorgt wird. Das Ventil 20, das ein Magnetventil sein kann, der Drucksammler 21 und die Pumpe 22 sind in Fig. 4 nur schematisch dargestellt.Another blowpipe 13, which extends through one of the side walls 7 of the turning chamber 4, is intended to blow air pressure surges tangentially or at a small angle over the partition 16 in the area where the inflow openings of the smoke pipes 9 are arranged. 4 and 5, the blow pipe 13 is connected via a valve 20 to a pressure collector 21, which is supplied with air pressure by a pressure pump 22. The valve 20, which can be a solenoid valve, the pressure collector 21 and the pump 22 are only shown schematically in FIG. 4.

Durch die Blasrohre 12 kann ein Teil der Verbrennungsluft eingeblasen werden, was sich günstig auf die Erzielung geringer Gehalte an CO und NOx auswirkt. Weiterhin können diese Blasrohre Dampf oder Druckluft in konstanter Weise kontinuierlich oder in Stößen zuführen.Part of the combustion air can be blown in through the blowpipes 12, which has a lower effect on the achievement Levels of CO and NO x affects. Furthermore, these blowpipes can supply steam or compressed air in a constant manner continuously or in bursts.

Für die Reinhaltung der Einströmöffnungen der Rauchrohre 9 genügt es, wenn über das Blasrohr 13 Druckstöße in zeitlichen Abständen von 0,5 bis 4 h zugeführt werden. Alternativ ist es aber auch möglich, über das Blasrohr kontinuierlich Luft zuzuführen, um die Abgaszusammensetzung zu beeinflussen.To keep the inflow openings of the smoke pipes 9 clean, it is sufficient if 13 pressure surges are supplied via the blow pipe at intervals of 0.5 to 4 hours. Alternatively, however, it is also possible to continuously supply air through the blow pipe in order to influence the exhaust gas composition.

In Fig. 2, die einen Schnitt längs der Linie A-A von Fig. 1 darstellt, erkennt man die Wendekammer 4 mit Blick auf das Flammrohr 2 und die Rauchrohre 9. Man sieht das Flammrohr 2, darunter ein Blasrohr 12, die Wassersammler 5, 6' und 6". Die unteren Wassersammler 6' und 6" sind exzentrisch angeordnet und erlauben der Strahlwirkung des Blasrohrs 13 bei Ausbreitung in dem bekannten Strahlwinkel die Gesamtheit der Einströmöffnungen der Rauchrohre 9 zu erfassen und Ablagerungen, die sich dort auf der Trennwand 16 gebildet haben könnten, wegzublasen. Aus diesem Grunde ist die Bodenwand 23 der Wendekammer 4 zweckmäßigerweise geneigt angeordnet und führt zu der schon erwähnten Öffnung zwischen den beiden unteren Wassersammlern 6' und 6" in den erwähnten Trog 24.2, which shows a section along the line AA of FIG. 1, the turning chamber 4 can be seen with a view of the flame tube 2 and the flue tubes 9. The flame tube 2, including a blow tube 12, the water collectors 5, 6 can be seen 'and 6 ". The lower water collectors 6' and 6" are arranged eccentrically and allow the jet effect of the blowpipe 13 when spreading in the known jet angle to record the entirety of the inflow openings of the smoke pipes 9 and deposits that have formed there on the partition 16 could blow away. For this reason, the bottom wall 23 of the turning chamber 4 is expediently arranged in an inclined manner and leads to the opening already mentioned between the two lower water collectors 6 ′ and 6 ″ in the mentioned trough 24.

Fig. 3 zeigt einen Schnitt durch den Einströmbereich eines der Rauchrohre 9 an der Trennwand 16, die die Kesseltrommel 1 von der Wendekammer 4 trennt. Das Rauchrohr 9 hat einen Innenradius R und ist am Einströmende trompetenartig ausgerundet mit einem inneren Krümmungsradius r. Die Ausrundung hat eine axiale Länge etwa der Größe r.FIG. 3 shows a section through the inflow region of one of the smoke pipes 9 on the partition wall 16, which separates the boiler drum 1 from the turning chamber 4. The smoke pipe 9 has an inner radius R and is rounded at the inflow end in a trumpet-like manner with an inner radius of curvature r. The fillet has an axial length of approximately size r.

Dieser Bereich ist besonders kritisch im Hinblick auf Ablagerungen von brennenden, sich noch in teigigem Zustand befindlichen Ascheteilchen. Diese könnten beim Einströmen in das Rauchrohr 9 einer zu scharfen Umlenkung als Folge eines zu kleinen inneren Krümmungsradius r nicht ganz folgen und um den Einlauf in das Rauchrohr 9 herum kragenartige Niederschläge bilden, die durch die Kühlwirkung der wassergekühlten Wände erstarren und sehr harte Krusten bilden. Solche Niederschläge werden dadurch vermieden, daß gemäß der Erfindung das Verhältnis r:R größer als 0,30, bevorzugt zwischen 0,50 und 0,80 dimensioniert wird.This area is particularly critical with regard to deposits of burning ash particles that are still in a doughy state. When flowing into the smoke tube 9, these could not entirely follow a deflection which is too sharp as a result of an inner radius of curvature r which is too small, and collar-like precipitation around the inlet into the smoke tube 9 form, which solidify due to the cooling effect of the water-cooled walls and form very hard crusts. Such precipitation is avoided by dimensioning the ratio r: R greater than 0.30, preferably between 0.50 and 0.80, according to the invention.

Diese Maßnahme allein reich jedoch zur Sauberhaltung des Rauchrohreinlaufes nicht aus. Bei zu kleinen Gasgeschwindigkeiten in den Rauchrohren 9 kommt es zum Ausfall von Asche entlang der Rauchrohre 9, die deren Boden bedecken und nach kurzer Zeit eine dünenartige Gestalt annehmen. Die Kämme der Dünen wandern im Betrieb mit einer Geschwindigkeit von etwa 1 m/s, also erheblich langsamer als die Geschwindigkeit der Rauchgase, die durch die Rauchrohre 9 strömen. Bei Erreichen des Austrittsquerschnitts eines Rauchrohres erzeugt jeder Dünenkamm einen Druckstoß, der kurzzeitig eine hohe Rauchgasgeschwindigkeit in dem Rauchrohr 9 zur Folge hat, worauf die Strömungsgeschwindigkeit der Rauchgase durch die Bildung der nächsten Dünenkämme wieder herabgesetzt wird. Dieser unregelmäßige Wechsel der Rauchgasgeschwindigkeit in den Rauchrohren 9 trägt wesentlich zur Bildung von kragenartigen Ascheverkrustungen im Bereich der Einströmöffnungen der Rauchrohre 9 bei. Dies wird erfindungsgemäß weiter dadurch vermieden, daß durch geeignete Dimensionierung von Anzahl und Querschnitten der Rauchrohre 9 die Rauchgasgeschwindigkeit am Querschnitt B, wo der zylindrische Bereich der Rauchrohre 9 beginnt, so eingestellt wird, daß der zugehörige Staudruck stets größer als 40 Pa ist und von dieser Grenze einen Sicherheitsabstand einhält. Bevorzugt liegt der Staudruck im Bereich zwischen 80 und 200 Pa. Noch höhere Staudrucke können zu dynamischen Effekten (Pulsationen) der Masse der Rauchgase in den Rauchrohren 9 im Zusammenwirken mit der Elastizität und der Energiezufuhr der heißen Gase im Flammrohr 2 führen. Dies bedeutet, daß der Bereich der Staudrucke von 40 bis 200 Pa für den Regelbereich des Rauchgasdurchsatzes zur Verfügung steht. Da der Staudruck quadratisch mit der Geschwindigkeit geht, ergibt sich daraus ein Regelbereich im Rauchgasdurchsatz von etwa 1 : 2,5. Dabei enthält auch der obere Wert von 200 Pa noch einen Sicherheitsabstand nach oben.However, this measure alone is not sufficient to keep the smoke pipe inlet clean. If the gas velocities in the flue pipes 9 are too low, ash is lost along the flue pipes 9, which cover the bottom thereof and take on a dune-like shape after a short time. The ridges of the dunes migrate in operation at a speed of approximately 1 m / s, that is to say considerably slower than the speed of the flue gases which flow through the flue pipes 9. When the outlet cross section of a smoke pipe is reached, each dune crest generates a pressure surge, which briefly results in a high smoke gas velocity in the smoke pipe 9, whereupon the flow velocity of the smoke gases is reduced again by the formation of the next dune crests. This irregular change in the flue gas velocity in the flue pipes 9 contributes significantly to the formation of collar-like ash incrustations in the area of the inflow openings of the flue pipes 9. This is further avoided according to the invention in that, by appropriately dimensioning the number and cross sections of the flue pipes 9, the flue gas velocity at cross section B, where the cylindrical region of the flue pipes 9 begins, is set so that the associated dynamic pressure is always greater than 40 Pa and from this Border maintains a safety distance. The dynamic pressure is preferably in the range between 80 and 200 Pa. Even higher dynamic pressures can lead to dynamic effects (pulsations) of the mass of the smoke gases in the smoke tubes 9 in cooperation with the elasticity and the energy supply of the hot gases in the flame tube 2. This means that the back pressure range of 40 to 200 Pa is available for the control range of the flue gas throughput. Since the dynamic pressure is quadratic with the speed, this results in a control range in the flue gas throughput of approximately 1: 2.5. Here the upper value of 200 Pa also contains a safety margin upwards.

Zur Optimierung der CO- und NOx-Werte können im Bereich der Wendekammer 4 weitere Blasrohre 17 vorgesehen sein, die insbesondere dann, wenn im Bereich des Flammrohraustrittsquerschnitts in die Wendekammer noch brennende Überkornteilchen vorhanden sind, diesen weiteren Sauerstoff für den Ausbrand zuführen. Diese Blasrohre 17 können zweckmäßigerweise derart angeordnet werden, daß in allen Eintrittsquerschnitten B der Rauchrohre 9 gleiche Sauerstoffgehalte vorhanden sind.To optimize the CO and NO x values, further blowpipes 17 can be provided in the area of the turning chamber 4, which in particular if there are still oversized particles in the area of the flame tube outlet cross section into the turning chamber, supply this further oxygen for the burnout. These blowpipes 17 can expediently be arranged such that the same oxygen contents are present in all inlet cross sections B of the flue pipes 9.

An der hinteren Stirnwand 8 der Wendekammer 4 können Türen 14 angeordnet sein, durch die die Einströmöffnungen der Rauchrohre 9 und der untere Bereich des Flammrohrs 2 zugänglich sind.Doors 14 can be arranged on the rear end wall 8 of the turning chamber 4, through which the inflow openings of the smoke tubes 9 and the lower region of the flame tube 2 are accessible.

In Fig. 4 erkennt man eine Ausführungsform der Erfindung, bei der in einer Kesseltrommel 1 zwei Flammrohre 2 angeordnet sind, von denen in Fig. 4 allerdings nur eines aus Übersichtlichkeitsgründen dargestellt ist. Das andere Flammrohr mit zugehöriger Wendekammer und anderen Bestandteile muß man sich spiegelbildlich angeordnet vorstellen. Man erkennt in Fig. 4 bei abgenommen Stirnwanddeckel 14 das Feld der Einströmöffnungen in die Rauchrohre 9 und ferner das Blasrohr 13 mit Ventil 20 und Drucksammler 21, wobei der Blasquerschnitt des Blasrohrs 13 strichpunktiert dargestellt ist und, wie erkenntlich, das gesamte Feld der Einströmöffnungen der Rauchrohre 9 überstreicht. Die Strömungsrichtung des Blasrohres 13 ist im wesentlichen schräg abwärts gerichtet, um weggeblasene Ascheablagerungen in den Austritt zwischen den unteren Wassersammlern 6' und 6" zu blasen. Man erkennt ferner in Fig. 4 unter der schrägen Bodenwand 23 der Wendekammer ein Zuführrohr 25 für Zusatzluft, das in die Wendekammer 4 mündende Austritte hat, die strichpunktiert schematisch angedeutet sind.FIG. 4 shows an embodiment of the invention in which two flame tubes 2 are arranged in a boiler drum 1, of which only one is shown in FIG. 4 for reasons of clarity. The other flame tube with associated turning chamber and other components must be imagined to be arranged in mirror image. One can see in FIG. 4 with the end wall cover 14 removed, the field of the inflow openings into the flue pipes 9 and also the blow pipe 13 with valve 20 and pressure collector 21, the blow cross section of the blow pipe 13 being shown in dash-dot lines and, as can be seen, the entire field of the inflow openings of the Smoke pipes 9 sweeps. The direction of flow of the blow pipe 13 is directed essentially obliquely downwards in order to blow away ash deposits which have been blown away into the outlet between the lower water collectors 6 'and 6 ". Furthermore, a feed pipe 25 for additional air can be seen in FIG. 4 under the sloping bottom wall 23 of the turning chamber. which has outlets opening into the turning chamber 4, which are indicated schematically by dash-dotted lines.

Fig. 5 zeigt die Anordnung nach Fig. 4 von oben, wobei man zwei Wendekammern erkennt, die als Zwillingsanordnung beiderseits der Mitte der Kesseltrommel 1 angeordnet sind. Im dargestellten Beispiel ist aus Übersichtlichkeitsgründen nur eines der Blasrohre 13 mit angesetztem Drucksammler 21 dargestellt, wobei diese Figur im wesentlichen zeigen soll, daß das Blasrohr 13 annähernd tangential über die Trennwand 16 bläst, die die Kesseltrommel 1 von den Wendekammern 4 trennt.FIG. 5 shows the arrangement according to FIG. 4 from above, wherein two turning chambers can be seen, which are arranged as a twin arrangement on both sides of the center of the boiler drum 1. In the example shown, for reasons of clarity, only one of the blowpipes 13 is shown with the pressure accumulator 21 attached, this figure essentially showing that the blowpipe 13 blows approximately tangentially over the partition wall 16 which separates the boiler drum 1 from the turning chambers 4.

Die Kesselkonstruktion ist auch geeignet für die Verbrennung von flüssigen, schwefelhaltigen Brennstoffen, wenn den heißen Verbrennungsgasen in oder kurz nach der Flamme ein kalkhaltiges Absorbens, beispielsweise Kalkhydrat zugesetzt wird. Solche staubförmige Beimengungen verhalten sich dann ähnlich wie die Asche bei aschehaltigen, staubförmigen Brennstoffen.The boiler construction is also suitable for the combustion of liquid, sulfur-containing fuels if a calcareous absorbent, for example hydrated lime, is added to the hot combustion gases in or shortly after the flame. Such dusty admixtures then behave similarly to the ash with ashy, dusty fuels.

Gleiches gilt für schwefel- und aschehaltige Brennstoffe, bei denen der Schwefel durch Niedertemperaturentschwefelung in die Asche eingebunden werden soll. Dies gelingt insbesondere dann gut, wenn die Asche genügend kalkhaltige oder ähnlich aktive Komponenten enthält, oder wenn dem Brennstoff ein kalkhaltiges Absorbens zugesetzt wird. Bei der Verbrennung solcher Brennstoffe in dem erfindungsgemäßen Flammrohrkessel ergibt sich eine besonder oberflächenaktive Asche bzw. eine besondere Aktivierung der kalkhaltigen Komponenten, sodaß bei Abkühlung der Rauchgase herab bis auf 10 bis 15°C über dem jeweiligen tatsächlichen Taupunkt der Verbrennungsabgase eine vollständige Einbindung des Schwefels in die Asche oder die kalkhaltigen Komponenten erfolgt.The same applies to fuels containing sulfur and ash, in which the sulfur is to be incorporated into the ash by low-temperature desulfurization. This works particularly well if the ash contains enough calcareous or similarly active components, or if a calcareous absorbent is added to the fuel. The combustion of such fuels in the flame tube boiler according to the invention results in a particularly surface-active ash or a special activation of the calcareous components, so that when the flue gases are cooled down to 10 to 15 ° C. above the respective actual dew point of the combustion exhaust gases, the sulfur is completely incorporated in the ashes or the calcareous components occur.

Bei dem erfindungsgemäßen Flammrohrkessel ergeben sich am Austrittsquerschnitt des Flammrohres 2 in die Wendekammer 4 Abgastemperaturen, die kleiner sind, als die Erweichungstemperatur der ausgebrannten Ascheteilchen. In Kesseln üblicher Größe können in Flammrohren Teilchen bis 0,2 bis 0,3 mm Korngröße ausbrennen. Größere Teilchen treten in brennendem, teigigem Zustand in die Wendekammer 4 und die Rauchrohre 9 ein. Die Erweichungstemperaturen der ausgebrannten Asche der verschiedenen Kohlenstaubsorten liegen überlicherweise zwischen 950 und 1250°C. Der Kessel ist daher zur Vermeidung des Anbackens solcher Ascheteilchen derart ausgelegt, daß die Rauchgase am Austritt aus dem Austrittsquerschnitt des Flammrohres 2 eine Temperatur haben, die um einen Sicherheitsabstand unter der genannten Ascheerweichungstemperatur liegt.In the flame tube boiler according to the invention, exhaust gas temperatures which are lower than the softening temperature of the burnt-out ash particles result at the outlet cross section of the flame tube 2 into the turning chamber 4. In boilers of normal size, particles up to 0.2 to 0.3 mm grain size can burn out in flame tubes. Larger particles enter the turning chamber 4 and the flue pipes 9 in a burning, doughy state a. The softening temperatures of the burnt-out ashes of the different types of coal dust are usually between 950 and 1250 ° C. The boiler is therefore designed to prevent such ash particles from caking in such a way that the flue gases at the outlet from the outlet cross section of the flame tube 2 have a temperature which is a safety distance below the ash softening temperature mentioned.

Am Austrittsende der Rauchrohre 9 unterhalb des Ansatzes 3 für den Brenner ist ein Rauchgassammelraum 18 zum Abzug der abgekühlten Rauchgase angeordnet. Dieser weist eine Zugangstür 19 auf, durch die das Innere der Rauchrohre 9 inspiziert und im Störungsfall in üblicher Weise mittels Durchstoßen mit langen Stangen gereinigt werden kann, wobei die herausgestoßenen Ablagerungen in den Trog 24 fallen und von der Schnecke 10 abtransportiert werden können.At the outlet end of the flue pipes 9 below the neck 3 for the burner, a flue gas collecting space 18 is arranged for extracting the cooled flue gases. This has an access door 19 through which the interior of the flue pipes 9 can be inspected and, in the event of a malfunction, cleaned in the usual way by piercing with long rods, the deposits which have fallen out falling into the trough 24 and being able to be removed by the screw 10.

Claims (13)

  1. A fire-tube boiler containing, in a boiler drum (1), at least one horizontally arranged fire tube (2) which is provided at one end with an extension (3) for the connecting of the burner, a reversing chamber (4) at one end of the boiler drum into which an outlet of the fire tube debouches at the other end thereof, and a plurality of flue tubes (9) which have an inside diameter 2R and extend, starting from the reversing chamber, below the fire tube through the boiler drum, characterized by the fact that
    -- each of the flue tubes (9) has an inlet opening which widens from the inside diameter (2R) in the direction towards the reversing chamber (4) into which it debouches, in trumpet-like manner with a radius of curvature r over an axial distance of approximately r, r/R being > 0.3,
    -- the dimensions of the fire tube (2), with due consideration of the boiler capacity and the desired temperature of the boiler water, are so selected that, in operation, the temperature of the flue gases at the outlet end of the fire tube (2) lies a safety margin below the ash-softening temperature of the corresponding fuel, and
    -- the number and inside diameter (2R) of the flue tubes (9) are so dimensioned that the dynamic pressure in the flue tubes (9) at a point (B) directly behind the trumpet-shaped widening is greater than 40 Pa.
  2. A fire-tube boiler according to Claim 1, characterized by the fact that said ratio is 0.8 > r/R > 0.5.
  3. A fire-tube boiler according to Claim 1 or 2, characterized by the fact that the number and the inside diameter (2R) of the flue tubes (9) are so dimensioned that the dynamic pressure in the flue tubes (9) at the point (B) directly behind the trumpet-shaped widening is between 80 and 200 Pa.
  4. A fire-tube boiler according to any of Claims 1 to 3, characterized by the fact that the fire tube (2) is provided, below the extension (3) for the connection of a burner, with at least one blast tube (12) which debouches into the fire tube (2).
  5. A fire-tube boiler according to any of Claims 1 to 4, characterized by the fact that the reversing chamber (4) is provided with a plurality of blast tubes (17) which have mouths which are opposite the inlet openings of the flue tubes (9).
  6. A fire-tube boiler according to any of the preceding claims, characterized by the fact that at least one side wall (7) of the reversing chamber (4) is passed through by at least one blast tube (13) the direction of blast of which is at least approximately parallel to a partition wall (16) having the flue-tube inlet opening which separates the reversing chamber (4) from the boiler drum (1) and the cross section of the blast jet of which passes over all flue tube inlet openings.
  7. A fire-tube boiler according to Claim 6, characterized by the fact that said at least one blast tube (12) is connected via a valve (20) to a gas pressure accumulator (21).
  8. A fire-tube boiler according to Claim 6 or 7, characterized by the fact that the direction of the jet of at least one blast tube (13) forms an angle of about 10° with the partition wall (16).
  9. A fire-tube boiler according to any of the preceding claims, characterized by the fact that the reversing chamber (4) has an ash outlet (24, 10) in its lower region.
  10. A fire-tube boiler according to Claim 9, characterized by the fact that the reversing chamber has an obliquely downward extending bottom wall (23) and the ash outlet (24, 10) is arranged asymmetric to the center plane of the reversing chamber (4) at the lower end of the bottom wall (23).
  11. A fire-tube boiler according to either of Claims 9 and 10, characterized by the fact that a blast tube (17) the direction of blast of which is directed at the ash outlet (24, 10) debouches into the reversing chamber (4) in the lower region thereof.
  12. A fire-tube boiler according to any of Claims 1 to 5, characterized by the fact that a side wall (7) of the reversing chamber (4) is passed through by a blast tube (13) the direction of blast of which is at least approximately parallel to a partition wall (16) having the flue tube inlet openings which separates the reversing chamber (4) from the boiler drum (1) and the cross section of the blast jet of which passes over all flue tube inlet openings; that said blast tube (13) is connected via a valve (20) to a gas pressure accumulator (21), the reversing chamber (4) has an oblique bottom wall (23) which extends obliquely downward commencing from the side wall (7) having the blast tube (13); and that an ash-outlet (24, 10) is arranged at the lower end of the bottom wall (23) asymmetric to the center plane of the reversing chamber (4).
  13. A fire-tube boiler according to any of the preceding claims, characterized by the fact that the flue tubes (9) debouch at the outlet side into a flue-gas collecting space (18) which has an access door (19) for inspecting the inside of the flue tubs (sic).
EP92906303A 1992-03-05 1992-03-05 Flame tube boiler Expired - Lifetime EP0629273B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4206969A DE4206969A1 (en) 1992-03-05 1992-03-05 Flame tube boiler for forming ash in fuel - has turn round chamber connected to one end and burner connected to other end with tubes for combustion gases
PCT/DE1992/000190 WO1993018339A1 (en) 1992-03-05 1992-03-05 Flame tube boiler

Publications (2)

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EP0629273A1 EP0629273A1 (en) 1994-12-21
EP0629273B1 true EP0629273B1 (en) 1996-09-11

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US (1) US5558046A (en)
EP (1) EP0629273B1 (en)
AT (1) ATE142764T1 (en)
CZ (1) CZ283961B6 (en)
DE (3) DE59207146D1 (en)
ES (1) ES2093252T3 (en)
HU (1) HU216756B (en)
PL (1) PL169337B1 (en)
RU (1) RU2091665C1 (en)
WO (1) WO1993018339A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2837262A1 (en) 2002-03-13 2003-09-19 Fritz Schoppe Cooler for hot dust-laden gases has plate with tube inlets having two different radii of curvature connected to inner surfaces to tubes at a tangent

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PL169337B1 (en) 1996-07-31
CZ205894A3 (en) 1994-12-15
CZ283961B6 (en) 1998-07-15
ES2093252T3 (en) 1996-12-16
HUT67842A (en) 1995-05-29
RU2091665C1 (en) 1997-09-27
ATE142764T1 (en) 1996-09-15
RU94041758A (en) 1996-08-27
EP0629273A1 (en) 1994-12-21
HU216756B (en) 1999-08-30
WO1993018339A1 (en) 1993-09-16
DE9218922U1 (en) 1996-02-29
DE4206969A1 (en) 1993-09-16
DE59207146D1 (en) 1996-10-17
US5558046A (en) 1996-09-24
HU9402362D0 (en) 1994-10-28
PL305049A1 (en) 1995-01-09

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