EP0199251B1 - Waste heat steam generator - Google Patents

Waste heat steam generator Download PDF

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Publication number
EP0199251B1
EP0199251B1 EP86105132A EP86105132A EP0199251B1 EP 0199251 B1 EP0199251 B1 EP 0199251B1 EP 86105132 A EP86105132 A EP 86105132A EP 86105132 A EP86105132 A EP 86105132A EP 0199251 B1 EP0199251 B1 EP 0199251B1
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EP
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Prior art keywords
heat exchanger
steam generator
generator according
waste heat
supply line
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EP86105132A
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German (de)
French (fr)
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EP0199251A1 (en
Inventor
Hermann Brückner
Winfried Dipl.-Ing. Ganzer
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Siemens AG
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Siemens AG
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
    • F22B1/1838—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines the hot gas being under a high pressure, e.g. in chemical installations
    • F22B1/1846—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines the hot gas being under a high pressure, e.g. in chemical installations the hot gas being loaded with particles, e.g. waste heat boilers after a coal gasification plant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B29/00—Steam boilers of forced-flow type
    • F22B29/02—Steam boilers of forced-flow type of forced-circulation type

Definitions

  • the invention relates to a heat recovery steam generator for hot, dust-laden, pressurized gases with a so-called heat exchanger space, which is arranged concentrically in a pressure vessel and is open at the lower end and carries the heat exchanger elements, with a gas supply line opening into the heat exchanger space, with a pressure vessel wall connected gas exhaust line and with heat exchanger elements through which a cooling medium flows
  • Heat recovery steam generators are known. They are used particularly in gas and steam turbine power plants. They serve to use the heat content of the hot exhaust gases of the gas turbine to generate additional live steam. They generally consist of a cylindrical or rectangular chimney-like structure in which the hot exhaust gases flow through the heat exchanger tubes of the convection heating surfaces of the final superheaters, reheaters, evaporators and economizers one after the other from bottom to top.
  • Such heat recovery steam generators are also used behind reduction systems and in chemical processes for heat recovery.
  • waste heat steam generators which are arranged behind combustion layers, it is also known to allow the combustion gases to flow into the waste heat boiler from top to bottom and to arrange the heat exchanger heating surfaces in reverse order (cf. fuel-thermal power 35, 1983, No. 11, pages 465 to 470, as well as issue No. 12, pages 499 to 504).
  • GB 653 540 discloses a heat exchanger in which the hot gas supply line opens into a heat exchanger space which is arranged concentrically in a pressure vessel and is open at the lower end and carries the heat exchanger elements, in which the gas discharge line is connected to the pressure vessel wall and with the space between the surrounding walls of the heat exchanger space and the pressure vessel is connected. But it is a peculiarity of this steam generator that it can only be used for dust-free gases, because otherwise the lower callot would clog and block the further gas flow. The necessary cooling of the gas supply line also leads to a reduction in the overall efficiency.
  • the invention has for its object to provide a waste heat steam generator for hot, dust-laden and at the same time pressurized gases, which works with the greatest possible efficiency, is inexpensive to manufacture and requires little space.
  • the full gas pressure can be absorbed by the cooler outer walls of the pressure vessel.
  • the peripheral walls of the heat exchanger space exposed to the hot gas flow need only absorb the pressure difference between the inflowing hot gas and the outflowing cooled gas.
  • This pressure difference is of the order of a few meters of water and is essentially determined by the flow resistance that the heat exchanger elements offer to the gas flow. For a given temperature resistance of the material of the pressure vessel wall, this measure allows the gas inlet temperature to be driven upward.
  • this structure also ensures that the outer wall of the pressure vessel of the heat recovery steam generator only must be insulated against a temperature that is approximately between 100 ° and 250 °. In this way, the cost of thermal insulation is also reduced and the heat loss can be significantly reduced.
  • the connection of the gas supply line at the upper end of a heat exchanger space which is open at the bottom results in less susceptibility to contamination by the dust particles carried along.
  • the thermally highly stressed gas supply line can be largely relieved of pressure loads and at the same time the heat loss can be reduced by the fact that the thermal insulation must be matched to the much lower temperature of the gas discharge line.
  • the stability of the surrounding walls as well as the gas supply line can be increased significantly if they carry the heat exchanger tubes in an advantageous development of the invention.
  • the figure shows the structure of the heat recovery steam generator 3 according to the invention connected between a coal gasifier 1 and a gas cleaning system 2.
  • the gas feed line 4 coming from the coal gasifier 1 leads centrally from top to bottom in a heat exchanger space 6 arranged in a pressure vessel 5.
  • This heat exchanger space is open at the bottom and opens there into the pressure vessel 5.
  • the space between the peripheral walls of the heat exchanger space 6 and the outer wall of the pressure vessel is in turn connected at the upper end of the pressure vessel to a pressure-proof gas discharge line 8 enclosing the gas supply line 4.
  • a branch 9, which leads to the gas cleaning system 2 is located on this gas exhaust line directly in front of the coal gasifier 1.
  • the bottom 10 of the pressure container 5 is funnel-shaped and carries an ash discharge device 11 at its lowest point. This device consists of an ash lock 12 with two valves 13, 14 connected in series.
  • the peripheral walls of the heat exchanger space 6 are designed as fin tube walls.
  • the superheater, evaporator and economiser heating surfaces are suspended in the heat exchanger space 6 on support tubes 19, 20 (only two shown) which are passed through the above-mentioned heat exchanger surfaces and through which the circulating water flows.
  • these support tubes 19, 20 are connected in parallel to the fin tubes of the surrounding walls 7 of the heat exchanger space 6.
  • the wall of the gas supply line 4 is also designed as a fin tube wall. Your fin tubes are connected in series with those of the surrounding walls 7.
  • the heat exchanger tubes of the economizer heating surfaces 18, the evaporator heating surfaces 17 and the fin tubes of the gas supply line 4 are connected on the output side to a common water-steam separation vessel 21.
  • the heated water is conveyed via a circulation pump 22 into two strands 25, 26 which can be acted upon independently by means of control valves 23, 24.
  • the water is conveyed into the evaporator heating surfaces 17 via one of these two strands 25 and into the fin tubes of the surrounding walls 7 of the heat exchanger space 6 and the support tubes 19, 20 connected in parallel via the other of these two strands 26.
  • the water of the circulation line 26 leaving the heat exchanger tubes of the surrounding walls 7 and the support tubes 19, 20 is passed into the heat exchanger tubes of the gas supply line 4.
  • the steam side of the water vapor separation vessel 21 is connected to the superheater heating surfaces 15, 16 which are connected in series with one another.
  • An injection cooler 28 for regulating the temperature of the live steam leaving the last superheater 15 via the live steam line 29 is installed in the steam line 27 connecting the two superheater heating surfaces.
  • a feed water line 30 coming from the condenser (not shown further here) is connected via a feed water pump 31 to the input of the economizer 18.
  • the hot, dust-containing raw gas generated there flows via the gas feed line 4 from above into the heat exchanger space 6 of the heat recovery steam generator 3.
  • This gas has a temperature of about 1000 to 1400 ° C and due to the charging of the coal gasifier 1 a pressure of 10 to 60 bar. It is heavily loaded with dust particles. It flows through the two superheater heating surfaces 15, 16 in the heat exchanger space 6, then the evaporator heating surfaces 17 and finally the economizer heating surfaces 18 in order to flow into the pressure vessel 5 at the lower open end of the heat exchanger space 6, largely cooled, and to be deflected there by 180 °. Outside the peripheral walls 7 of the heat exchanger space 6, but within the pressure vessel 5, the cooled raw gas flows upwards again.
  • the dust particles are thrown by the deflection by 180 ° as well as by gravity into the ash funnel in the bottom 10 of the pressure vessel.
  • the ash can be removed there via the ash discharge device 11.
  • the gas which has been largely freed of ash and cooled to 150 to 400 ° C., now flows upwards in the pressure vessel 5 and almost back to the coal gasifier 1 via the gas discharge line 8 surrounding the gas supply line 4. Via the branch 9 in the gas exhaust line 8, it flows to the gas cleaning system 2. On this way back, it also cools the gas supply line 4 and supports it with its pressure, so that the gas supply line 4 only the differential pressure between those flowing into the heat recovery steam generator 3 and those leaving it Gas flow must take up.
  • Fresh feed water is fed into the economizer heating surfaces 18 through the feed water line 30 via the feed water pump 31.
  • the heated feed water leaving the economizer heating surfaces 18 is partly fed into the evaporator heating surfaces 17 via the water-steam separating vessel 21, the circulating pump 22 and, from there, mixed with steam and conveyed back into the water vapor separating vessel 21.
  • Parallel to the evaporator heating surfaces 17, part of the heated feed water is also conveyed into the heat exchanger tubes of the surrounding walls 7 of the heat exchanger chamber 6 and the gas supply line 4.
  • the steamed feed water is also conveyed into the water-steam separation vessel 21. There, the feed water separated from the steam is fed back to the circulation pump 22.
  • the steam passes from the water vapor separation vessel 21 into the two superheater heating surfaces 15, 16 connected in series. From the second superheater heating surface 15, the steam flows directly via the live steam line 29 to the consumer.
  • the quality of the live steam can also be regulated by the injection cooler 28 connected between the two superheater heating surfaces in the steam line.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Chimneys And Flues (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)

Description

Die Erfindung bezieht sich auf einen Abhitzedampferzeuger für heiße, staubbeladene, unter Überdruck stehende Gase mit einem in einen konzentrisch in einem Druckbehalter angeordneten, am unteren Ende offenen, die Wärmetauscherelemente tragenden sogenannten Wärmetauscherraum, mit einer in den Wärmetauscherraum mündenden Gaszuführungsleitung, mit einer an der Druckbehälterwand angeschlossenen Gasabzugsleitung sowie mit von einem Kühlmedium durchströmten WärmetauscherelementenThe invention relates to a heat recovery steam generator for hot, dust-laden, pressurized gases with a so-called heat exchanger space, which is arranged concentrically in a pressure vessel and is open at the lower end and carries the heat exchanger elements, with a gas supply line opening into the heat exchanger space, with a pressure vessel wall connected gas exhaust line and with heat exchanger elements through which a cooling medium flows

Abhitzedampferzeuger sind bekannt. Sie werden insbesondere in Gas- und Dampfturbinenkraftwerken verwandt. Sie dienen dazu den Wärmeinhalt der heißen Abgase der Gasturbine zur Erzeugung zusätzlichen Frischdampf es heranzuziehen. Sie bestehen im allgemeinen aus einem zylindrischen oder rechteckigen kaminartigen Gebilde, in dem die heißen Abgase von unten nach oben nacheinander die Wärmetauscherrohre der Konvektionsheizflächen der Endüberhitzer, Zwischenüberhitzer, Verdampfer und Economiser durchströmen.Heat recovery steam generators are known. They are used particularly in gas and steam turbine power plants. They serve to use the heat content of the hot exhaust gases of the gas turbine to generate additional live steam. They generally consist of a cylindrical or rectangular chimney-like structure in which the hot exhaust gases flow through the heat exchanger tubes of the convection heating surfaces of the final superheaters, reheaters, evaporators and economizers one after the other from bottom to top.

Auch hinter Reduktionsanlagen und bei chemischen Prozessen werden zur Wärmerückgewinnung solche Abhitzedampferzeuger eingesetzt. Bei Abhitzedampferzeugern, die hinter Verbrennungslagen angeordnet sind, ist es auch bekannt, die Verbrennungsgase von oben nach unten in den Abhitzekessel strömen zu lassen und dafür die Wärmetauscherheizflächen in umgekehrter Reihenfolge anzuordnen (vgl. Brennstoff-Wärmekraft 35,1983, Heft Nr. 11, Seiten 465 bis 470, sowie Heft Nr. 12, Seiten 499 bis 504).Such heat recovery steam generators are also used behind reduction systems and in chemical processes for heat recovery. In waste heat steam generators, which are arranged behind combustion layers, it is also known to allow the combustion gases to flow into the waste heat boiler from top to bottom and to arrange the heat exchanger heating surfaces in reverse order (cf. fuel-thermal power 35, 1983, No. 11, pages 465 to 470, as well as issue No. 12, pages 499 to 504).

Eine Variante solcher Abhitzedampferzeuger, welche auch für staubbeladene Gase geeignet ist, ist durch die GB-A-2 068 095 bekannt geworden. Hier strömen die heißen Abgase zunächst von unten nach oben in einen vertikal angeordneten, in einen Druckbehälter eingebauten Strahlungsraum, der frei von Einbauten gehalten ist und werden am oberen Ende dieses Strahlungsraumes abgezogen und in einen zweiten Wärmetauscherelemente tragenden Wärmetauscherraum geleitet, der unten offen ist und in einem zweiten Druckbehälter eingebaut ist und von oben nach unten durchströmt wird. Diese beiden Druckbehälter sind am unteren Ende mit trichterförmigen Öffnungen zur Entfernung von Staub und Asche versehen. Es ist eine Eigenart dieser Abhitzedampferzeugeranlage, daß der technische Aufwand beträchtlich ist und daß der Gesamtwirkungsgrad durch die großen Wärme abstrahlenden Oberflächen begrenzt ist. Darüber hinaus ist die höchstzulässige Gaseintrittstemperatur durch die Temperaturbeständigkeit der Druckbehälterwand am heißen Ende des Strahlungsraumes begrenzt.A variant of such heat recovery steam generator, which is also suitable for dust-laden gases, has become known from GB-A-2 068 095. Here, the hot exhaust gases first flow from the bottom upwards into a vertically arranged radiation chamber, which is installed in a pressure vessel and is kept free of internals, and are withdrawn at the upper end of this radiation chamber and passed into a second heat exchanger chamber which carries heat exchanger elements and is open at the bottom and in a second pressure vessel is installed and flows through from top to bottom. These two pressure vessels are provided with funnel-shaped openings at the lower end to remove dust and ash. It is a peculiarity of this heat recovery steam generator system that the technical effort is considerable and that the overall efficiency is limited by the large heat-radiating surfaces. In addition, the maximum permissible gas inlet temperature is limited by the temperature resistance of the pressure vessel wall at the hot end of the radiation chamber.

Bei der Wärmerückgewinnung der Abgase von Kohledruckvergasungsanlagen ergeben sich zusätzliche Probleme dadurch, daß zur hohen Gastemperatur ein hoher Gasdruck sowie eine starke Staubbeladung und Aggressivität der Gase hinzukommt. Zur Wärmerückgewinnung in solchen Anlagen ist es bekannt, die heißen Abgase in einem ersten mit Wärmetauscherheizflächen versehenen Druckbehälter vorzukühlen, sie sodann in einem nachgeschalteten Zyklon zur Entstaubung einzuleiten und anschließend in einem zweiten Druckbehälter weiter zu kühlen (GB 8 204 325 DE-OS 33 05 032).Additional problems arise in the heat recovery of the exhaust gases from coal pressure gasification plants in that, in addition to the high gas temperature, a high gas pressure and a strong dust loading and aggressiveness of the gases are added. For heat recovery in such systems, it is known to pre-cool the hot exhaust gases in a first pressure vessel provided with heat exchanger heating surfaces, then to introduce them in a downstream cyclone for dedusting and then to further cool them in a second pressure vessel (GB 8 204 325 DE-OS 33 05 032 ).

Durch die GB 653 540 ist ein Wärmetauscher bekannt geworden, bei dem die heiße Gaszuführungsleitung in einen konzentrisch in einem Druckbehälter angeordneten, am unteren Ende offenen, die Wärmetauscherelemente tragenden Wärmetauscherraum mündet, bei dem die Gasabzugsleitung an der Druckbehälterwand angeschlossen und mit dem Zwischenraum zwischen den Umfassungswänden des Wärmetauscherraumes und des Druckbehälters verbunden ist. Es ist aber eine Eigenart dieses Dampferzeugers, daß er nur für staubfreie Gase verwendbar ist, weil sich sonst die untere Kallotte zusetzen und den weiteren Gasdurchfluß blockieren würde. Auch führt die notwendige Kühlung der Gaszuführungsleitung zu einer Verminderung des Gesamtwirkungsgrades.GB 653 540 discloses a heat exchanger in which the hot gas supply line opens into a heat exchanger space which is arranged concentrically in a pressure vessel and is open at the lower end and carries the heat exchanger elements, in which the gas discharge line is connected to the pressure vessel wall and with the space between the surrounding walls of the heat exchanger space and the pressure vessel is connected. But it is a peculiarity of this steam generator that it can only be used for dust-free gases, because otherwise the lower callot would clog and block the further gas flow. The necessary cooling of the gas supply line also leads to a reduction in the overall efficiency.

Der Erfindung liegt die Aufgabe zugrunde, einen Abhitze-Dampferzeuger für heiße, staubbeladene und zugleich unter Überdruck stehende Gase zu schaffen, der mit einem möglichst großen Wirkungsgrad arbeitet, preiswert herstellbar ist und wenig Platz benötigt.The invention has for its object to provide a waste heat steam generator for hot, dust-laden and at the same time pressurized gases, which works with the greatest possible efficiency, is inexpensive to manufacture and requires little space.

Diese Aufgabe wird durch die Merkmale des Anspruchs 1 gelöst. Vorteilhafte Weiterbildungen sind in den Ansprüchen 2 bis 14 beschrieben.This object is solved by the features of claim 1. Advantageous further developments are described in claims 2 to 14.

Infolge der Anordnung des die Wärmetauscherelemente beinhaltenden sogenannten Wärmetauscherraumes im Innern eines Druckbehälters, dessen Außenwände von dem abgekühlten Gas bespült werden, kann der volle Gasdruck von den kühleren Außenwänden des Druckbehälters aufgenommen werden. Auf diese Weise brauchen die dem heißen Gasstrom ausgesetzten Umfassungswände des Wärmetauscherraumes lediglich die Druckdifferenz zwischen dem zuströmenden heißen Gas und dem abströmenden abgekühlten Gas aufzunehmen. Diese Druckdifferenz liegt in der Größenordnung von einigen Metern Wassersäule und wird im wesentlichen durch den Strömungswiderstand, den die Wärmetauscherelemente dem Gasstrom bieten, bestimmt. Diese Maßnahme erlaubt es bei gegebener Temperaturfestigkeit des Materials der Druckbehälterwand, die Gaseintrittstemperatur weiter nach oben zu treiben. Darüber hinaus wird durch diesen Aufbau auch erreicht, daß die Außenwand des Druckbehälters des Abhitzedampferzeugers nur gegen eine Temperatur wärmegedämmt werden muß, die etwa zwischen 100° und 250° liegt. Auf diese Weise verringert sich zugleich auch der Aufwand für die Wärmedämmung und kann der Wärmeverlust deutlich verringert werden. Der Anschluß der Gaszuführungsleitung am oberen Ende eines unten offenen Wärmetauscherraumes hat eine geringere Anfälligkeit gegen Verschmutzung durch die mitgeführten Staubteilchen zur Folge.As a result of the arrangement of the so-called heat exchanger space containing the heat exchanger elements inside a pressure vessel, the outer walls of which are flushed with the cooled gas, the full gas pressure can be absorbed by the cooler outer walls of the pressure vessel. In this way, the peripheral walls of the heat exchanger space exposed to the hot gas flow need only absorb the pressure difference between the inflowing hot gas and the outflowing cooled gas. This pressure difference is of the order of a few meters of water and is essentially determined by the flow resistance that the heat exchanger elements offer to the gas flow. For a given temperature resistance of the material of the pressure vessel wall, this measure allows the gas inlet temperature to be driven upward. In addition, this structure also ensures that the outer wall of the pressure vessel of the heat recovery steam generator only must be insulated against a temperature that is approximately between 100 ° and 250 °. In this way, the cost of thermal insulation is also reduced and the heat loss can be significantly reduced. The connection of the gas supply line at the upper end of a heat exchanger space which is open at the bottom results in less susceptibility to contamination by the dust particles carried along.

Infolge der unten offenen Bauweise des Wärmetauscherraumes und der erzwungenen Umkehrung der heißen Gase um 180° am unteren Ende des Wärmetauscherraumes erfolgt in Verbindung mit der am oberen Ende des Druckbehälters angeschlossenen Gasabzugsleitung durch die Wirkung der Schwerkraft und der diese unterstützenden Fliehkräfte eine besonders intensive Trennung der mitgeführten Staubpartikel von dem inzwischen weitgehend abgekühlten Gas und fallen diese Staubpartikel aufgrund ihrer Schwerkraft in die Vertiefung des Druckbehälterbodens. Wenn der Druckbehälterboden zugleich trichterförmig ausgebildet ist, lassen sich die am Boden ansammelnden Asche- und Staubpartikel über eine dort anzuschließende AscheAustragsvorrichtung abführen.As a result of the open design of the heat exchanger space and the forced reversal of the hot gases by 180 ° at the lower end of the heat exchanger space, in connection with the gas discharge line connected to the upper end of the pressure vessel, the effect of gravity and the centrifugal forces that support it result in a particularly intensive separation of those carried Dust particles from the now largely cooled gas and these dust particles fall into the depression of the pressure vessel bottom due to their gravity. If the pressure vessel bottom is also funnel-shaped, the ash and dust particles that collect on the bottom can be removed using an ash discharge device to be connected there.

Besonders vorteilhaft ist es, die Gaszuführungsleitung im Innern der Gasabzugsleitung zu führen. In diesem Fall kann auch die thermisch hoch beanspruchte Gaszuführungsleitung weitestgehend von Druckbeanspruchungen entlastet werden und kann zugleich der Wärmeverlust dadurch reduziert werden, daß die Wärmedämmung auf die wesentlich niedrigere Temperatur der Gasabzugsleitung abgestimmt werden muß.It is particularly advantageous to guide the gas supply line inside the gas discharge line. In this case, the thermally highly stressed gas supply line can be largely relieved of pressure loads and at the same time the heat loss can be reduced by the fact that the thermal insulation must be matched to the much lower temperature of the gas discharge line.

Die Standfestigkeit der Umfassungswände wie auch der Gaszuführungsleitung läßt sich bedeutend erhöhen, wenn diese in vorteilhafter Weiterbildung der Erfindung die Wärmetauscherrohre tragen.The stability of the surrounding walls as well as the gas supply line can be increased significantly if they carry the heat exchanger tubes in an advantageous development of the invention.

Weitere Einzelheiten der Erfindung sind anhand eines in der Figur dargestellten Ausführungsbeispiels erläutert.Further details of the invention are explained with reference to an embodiment shown in the figure.

Die Figur zeigt den Aufbau des zwischen einem Kohlevergaser 1 und einer Gasreinigungsanlage 2 geschalteten erfindungsgemäßen Abhitzedampferzeugers 3. Die vom Kohlevergaser 1 kommende Gaszuführungsleitung 4 mündet von oben nach unten führend zentral in in einem Druckbehälter 5 angeordneten Wärmetauscherraum 6. Dieser Wärmetauscherraum ist unten offen und mündet dort in den Druckbehälter 5. Der Zwischenraum zwischen den Umfassungswänden des Wärmetauscherraumes 6 und der Außenwand des Druckbehälters ist seinerseits am oberen Ende des Druckbehälters an einer druckfesten, die Gaszuführungszuleitung 4 umschließenden Gasabzugsleitung 8 angeschlossen. An dieser Gasabzugsleitung befindet sich unmittelbar vor dem Kohlevergaser 1 eine Abzweigung 9, die zur Gasreinigungsanlage 2 führt. Der Boden 10 des Druckbehälters 5 ist trichterförmig ausgebildet und trägt an seiner tiefsten Stelle eine Ascheaustragsvorrichtung 11. Diese besteht aus einer Aschenschleuse 12 mit zwei hintereinandergeschalteten Ventilen 13, 14.The figure shows the structure of the heat recovery steam generator 3 according to the invention connected between a coal gasifier 1 and a gas cleaning system 2. The gas feed line 4 coming from the coal gasifier 1 leads centrally from top to bottom in a heat exchanger space 6 arranged in a pressure vessel 5. This heat exchanger space is open at the bottom and opens there into the pressure vessel 5. The space between the peripheral walls of the heat exchanger space 6 and the outer wall of the pressure vessel is in turn connected at the upper end of the pressure vessel to a pressure-proof gas discharge line 8 enclosing the gas supply line 4. A branch 9, which leads to the gas cleaning system 2, is located on this gas exhaust line directly in front of the coal gasifier 1. The bottom 10 of the pressure container 5 is funnel-shaped and carries an ash discharge device 11 at its lowest point. This device consists of an ash lock 12 with two valves 13, 14 connected in series.

In dem Wärmetauscherraum 6 sind von oben nach unten zwei Überhitzerheizflächen 15, 16, eine Verdampferheizfläche 17 sowie ganz am unteren Ende des Wärmetauscherraumes 6 eine Economiserheizfläche 18 eingezeichnet. Die Umfassungswände des Wärmetauscherraumes 6 sind als Flossenrohrwände ausgebildet. Die Überhitzer-, Verdampfer- und Economiserheizflächen sind im Wärmetauscherraum 6 an Tragrohren 19, 20 (nur zwei dargestellt) aufgehängt, die durch die jeweils darüber angeordneten vorgenannten Wärmetauscherflächen hindurchgeführt sind und vom Umwälzwasser durchflossen werden. Diese Tragrohre 19, 20 sind im Ausführungsbeispiel parallel zu den Flossenrohren der Umfassungswände 7 des Wärmetauscherraumes 6 geschaltet. Auch die Wand der Gaszuführungsleitung 4 ist als Flossenrohrwand ausgebildet. Ihre Flossenrohre sind in Serie zu denjenigen der Umfassungswände 7 geschaltet. Die Wärmetauscherrohre der Economiserheizflächen 18, der Verdampferheizflächen 17 und die Flossenrohre der Gaszuführungsleitung 4 sind ausgangsseitig an ein gemeinsames Wasser-Dampf-Trenngefäß 21 angeschlossen. Von diesen wird das aufgeheizte Wasser über eine Umwälzpumpe 22 in zwei mittels Steuerventile 23, 24 unabhängig voneinander beaufschlagbaren Stränge 25, 26 gefördert. Über einen dieser beiden Stränge 25 wird das Wasser in die Verdampferheizflächen 17 und über den anderen dieser beiden Stränge 26 in die Flossenrohre der Umfassungswände 7 des Wärmetauscherraumes 6 und den diesen parallel geschalteten Tragrohren 19, 20 gefördert.In the heat exchanger space 6, two superheater heating surfaces 15, 16, an evaporator heating surface 17 and, at the very bottom of the heat exchanger space 6, an economizer heating surface 18 are shown. The peripheral walls of the heat exchanger space 6 are designed as fin tube walls. The superheater, evaporator and economiser heating surfaces are suspended in the heat exchanger space 6 on support tubes 19, 20 (only two shown) which are passed through the above-mentioned heat exchanger surfaces and through which the circulating water flows. In the exemplary embodiment, these support tubes 19, 20 are connected in parallel to the fin tubes of the surrounding walls 7 of the heat exchanger space 6. The wall of the gas supply line 4 is also designed as a fin tube wall. Your fin tubes are connected in series with those of the surrounding walls 7. The heat exchanger tubes of the economizer heating surfaces 18, the evaporator heating surfaces 17 and the fin tubes of the gas supply line 4 are connected on the output side to a common water-steam separation vessel 21. Of these, the heated water is conveyed via a circulation pump 22 into two strands 25, 26 which can be acted upon independently by means of control valves 23, 24. The water is conveyed into the evaporator heating surfaces 17 via one of these two strands 25 and into the fin tubes of the surrounding walls 7 of the heat exchanger space 6 and the support tubes 19, 20 connected in parallel via the other of these two strands 26.

Das die Wärmetauscherrohre der Umfassungswände 7 und die Tragrohre 19,20 verlassende Wasser des Umwälzstranges 26 wird in die Wärmetauscherrohre der Gaszuführungsleitung 4 geleitet. Die Dampfseite des Wasserdampftrenngefäßes 21 ist an die untereinander in Serie geschalteten Überhitzerheizflächen 15, 16, angeschlossen. In der die beiden Überhitzerheizflächen miteinander verbindenden Dampfleitung 27 ist ein Einspritzkühler 28 zur Regelung der Temperatur des den letzten Überhitzer 15 über die Frischdampfleitung 29 verlassenden Frischdampfes eingebaut. Eine vom hier nicht weiter dargestellten Kondensator kommende Speisewasserleitung 30 ist über eine Speisewasserpumpe 31 an den Eingang des Economisers 18 angeschlossen.The water of the circulation line 26 leaving the heat exchanger tubes of the surrounding walls 7 and the support tubes 19, 20 is passed into the heat exchanger tubes of the gas supply line 4. The steam side of the water vapor separation vessel 21 is connected to the superheater heating surfaces 15, 16 which are connected in series with one another. An injection cooler 28 for regulating the temperature of the live steam leaving the last superheater 15 via the live steam line 29 is installed in the steam line 27 connecting the two superheater heating surfaces. A feed water line 30 coming from the condenser (not shown further here) is connected via a feed water pump 31 to the input of the economizer 18.

Beim Betrieb des Kohlevergasers 1 strömt das dort erzeugte heiße, staubhaltige Rohgas über die Gaszuführungsleitung 4 von oben in den Wärmetauscherraum 6 des Abhitzedampferzeugers 3 hinein. Dieses Gas hat eine Temperatur von ca. 1000 bis 1400°C und infolge der Aufladung des Kohlevergasers 1 einen Druck von 10 bis 60 bar. Es ist stärk mit Staubpartikeln beladen. Es durchströmt im Wärmetauscherraum 6 zunächst die beiden Überhitzerheizflächen 15,16, sodann die Verdampferheizflächen 17 und schließlich die Economiserheizflächen 18 um weitgehend abgekühlt am unteren offenen Ende des Wärmetauscherraumes 6 in den Druckbehälter 5 einzuströmen und dort um 180° umgelenkt zu werden. Außerhalb der Umfassungwände 7 des Wärmetauscherraumes 6, jedoch innerhalb des Druckbehälters 5 strömt das abgekühlte Rohgas wieder nach oben. Hierbei werden die Staubteilchen sowohl durch die Umlenkung um 180° als auch unterstützend hierzu durch die Schwerkraft in den Aschetrichter im Boden 10 des Druckbehälters geschleudert. Die Asche kann dort über die Ascheaustragvorrichtung 11 entfernt werden. Das so weitgehend von Asche befreite und auf 150 bis 400° C abgekühlte Gas strömt nunmehr im Druckbehälter 5 nach oben und über die die Gaszuführungsleitung 4 umschließende Gasabzugsleitung 8 bis nahezu zum Kohlevergaser 1 zurück. Über die Abzweigung 9 in der Gasabzugsleitung 8 strömt es zur Gasreinigungsanlage 2. Auf diesem Rückweg kühlt es zugleich die Gaszuführungsleitung 4 und stützt sie mit ihrem Druck ab, so daß die Gaszuführungsleitung 4 nur den Differenzdruck zwischen den in den Abhitzedampferzeuger 3 einströmenden und den diesen verlassenden Gasstrom aufnehmen muß. Dies hat nicht nur den Vorteil, daß die thermisch stark beanspruchte Gaszuführungsleitung weitgehend druckentlastet ist, sondern, daß auch die Wärmeverluste geringer werden und die Isolation dieser koaxialen Gaszuführungs- und Gasabzugsleitung, wie auch des Abhitzedampferzeugers 3 stark vereinfacht wird, weil deren nur etwa 200° C heiß werdende Außenwände thermisch besser isolierbar sind.During operation of the coal gasifier 1, the hot, dust-containing raw gas generated there flows via the gas feed line 4 from above into the heat exchanger space 6 of the heat recovery steam generator 3. This gas has a temperature of about 1000 to 1400 ° C and due to the charging of the coal gasifier 1 a pressure of 10 to 60 bar. It is heavily loaded with dust particles. It flows through the two superheater heating surfaces 15, 16 in the heat exchanger space 6, then the evaporator heating surfaces 17 and finally the economizer heating surfaces 18 in order to flow into the pressure vessel 5 at the lower open end of the heat exchanger space 6, largely cooled, and to be deflected there by 180 °. Outside the peripheral walls 7 of the heat exchanger space 6, but within the pressure vessel 5, the cooled raw gas flows upwards again. Here, the dust particles are thrown by the deflection by 180 ° as well as by gravity into the ash funnel in the bottom 10 of the pressure vessel. The ash can be removed there via the ash discharge device 11. The gas, which has been largely freed of ash and cooled to 150 to 400 ° C., now flows upwards in the pressure vessel 5 and almost back to the coal gasifier 1 via the gas discharge line 8 surrounding the gas supply line 4. Via the branch 9 in the gas exhaust line 8, it flows to the gas cleaning system 2. On this way back, it also cools the gas supply line 4 and supports it with its pressure, so that the gas supply line 4 only the differential pressure between those flowing into the heat recovery steam generator 3 and those leaving it Gas flow must take up. This not only has the advantage that the thermally highly stressed gas supply line is largely relieved of pressure, but also that the heat losses are reduced and the insulation of this coaxial gas supply and gas exhaust line, as well as of the heat recovery steam generator 3, is greatly simplified, because only about 200 ° C external walls that become hot can be better insulated thermally.

Durch die Speisewasserleitung 30 wird über die Speisewasserpumpe 31 frisches Speisewasser in die Economiserheizflächen 18 eingespeist. Das die Economiserheizflächen 18 verlassende aufgewärmte Speisewasser wird über das Wasser-Dampf-Trenngefäß 21, die Umwälzpumpe 22 zum Teil in die Verdampferheizflächen 17 eingespeist und von dort mit Dampf durchsetzt in das 'Wasserdampftrenngefäß 21 zurückgefördert. Parallel zu den Verdampferheizflächen 17 wird auch ein Teil des aufgeheizten Speisewassers in die Wärmetauscherrohre der Umfassungswände 7 des Wärmetauscherraumes 6 und der Gaszuführungsleitung 4 gefördert. Von den Verdampferheizflächen, wie auch von der Gaszuführungsleitung 4 wird das mit Dampf durchsetzte Speisewasser ebenfalls in das Wasser-Dampftrenngefäß 21 gefördert. Dort wird das vom Dampf abgetrennte Speisewasser wieder der Umwälzpumpe 22 zugeführt. Der Dampf gelangt vom Wasserdampf-Trenngefäß 21 in die beiden in Serie geschalteten Überhitzerheizflächen 15, 16. Aus der zweiten Überhitzerheizfläche 15, strömt der Dampf direkt über die Frischdampfleitung 29 zum Verbraucher. Die Qualität des Frischdampfes kann noch durch die zwischen den beiden Überhitzerheizflächen in die Dampfleitung geschalteten Einspritzkühler 28 geregelt werden.Fresh feed water is fed into the economizer heating surfaces 18 through the feed water line 30 via the feed water pump 31. The heated feed water leaving the economizer heating surfaces 18 is partly fed into the evaporator heating surfaces 17 via the water-steam separating vessel 21, the circulating pump 22 and, from there, mixed with steam and conveyed back into the water vapor separating vessel 21. Parallel to the evaporator heating surfaces 17, part of the heated feed water is also conveyed into the heat exchanger tubes of the surrounding walls 7 of the heat exchanger chamber 6 and the gas supply line 4. From the evaporator heating surfaces, as well as from the gas supply line 4, the steamed feed water is also conveyed into the water-steam separation vessel 21. There, the feed water separated from the steam is fed back to the circulation pump 22. The steam passes from the water vapor separation vessel 21 into the two superheater heating surfaces 15, 16 connected in series. From the second superheater heating surface 15, the steam flows directly via the live steam line 29 to the consumer. The quality of the live steam can also be regulated by the injection cooler 28 connected between the two superheater heating surfaces in the steam line.

BezugszeichenlisteReference symbol list

Figure imgb0001
Figure imgb0001

Claims (15)

1. Waste heat steam generator for hot dust- laden gases at high pressure, having a heat exchanger chamber (6) arranged concentrically in a pressure tank (5), said heat exchanger chamber being open at its lower end and carrying the heat exchanger elements (15 to 18), a gas supply line (4) opening from the top into the heat exchanger chamber, a gas discharge line (8) connected to the pressure tank wall and joined to the intermediate space between the surrounding walls (7) of the heat exchanger chamber (6) and of the pressure tank (5), and heat exchanger elements through which coolant flows, characterised in that the gas supply line (4) is conducted inside the gas discharge line (8), the pressure tank base (10) is funnel-shaped and is connected to an ash removal device (11), and the surrounding walls (7) of the heat exchanger chamber (6) are provided with heat exchanger pipes.
2. Waste heat steam generator according to claim 1, characterised in that the wall of the gas supply line (4) carries heat exchanger pipes.
3. Waste heat steam generator according to claim 1, characterised in that the surrounding walls (7) of the heat exchanger chamber (6) are designed as fin pipe walls.
4. Waste heat steam generator according to claim 2, characterised in that the wall of the gas supply line (4) is designed as a fin pipe wall.
5. Waste heat steam generator according to claim 1, characterised in that the gas supply line (4) conducted concentrically in the gas discharge line (8) joins the heat exchanger chamber (6) to a coal gasifier (1).
6. Waste heat steam generator according to claim 1, characterised in that the gas supply line conducted concentrically in the gas discharge line joins the heat exchanger chamber to a combustion chamber.
7. Waste heat steam generator according to claim 5, characterised in that the gas discharge line (8) is connected to a gas purification installation (2).
8. Waste heat steam generator according to claim 1, characterised in that the heat exchanger elements (15 to 18) are mounted in the heat exchanger chamber (6) by means of heat exchanger pipes (19, 20) through which a coolant flows.
9. Waste heat steam generator according to claim 1, characterised in that water or steam is used as the coolant.
10. Waste heat steam generator according to claim 1 and 9, characterised in that the individual heat exchangers (15 to 18) of the heat exchanger chamber (6) are connected as forced circulation steam generators.
11. Waste heat steam generator according to claim 1 and 9, characterised in that the vaporiser heating surfaces (17) in the heat exchanger chamber (6) on the one hand and the heat exchanger pipes of the surrounding walls (7) of the heat exchanger chamber (6), their mounting pipes (19, 20) and the heat exchanger pipes of the gas supply line (4) on the other hand are connected as two separately controllable circulatory systems connected in parallel with each other.
12. Waste heat steam generator according to claim 11, characterised in that both circulatory systems (25, 26) are connected to one and the same steam-water-separating vessel (21).
13. Waste heat steam generator according to claim 11, characterised in that a separate control valve (23, 22) is associated with each circulatory system.
14. Waste heat steam generator according to claim 11, characterised in that a separate circulating pump is associated with each circulatory system.
EP86105132A 1985-04-26 1986-04-14 Waste heat steam generator Expired EP0199251B1 (en)

Applications Claiming Priority (2)

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DE19853515174 DE3515174A1 (en) 1985-04-26 1985-04-26 HEAT STEAM GENERATOR
DE3515174 1985-04-26

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US4738224A (en) 1988-04-19
EP0199251A1 (en) 1986-10-29
DE3515174A1 (en) 1986-11-06
AU583614B2 (en) 1989-05-04
AU5659786A (en) 1986-10-30
DE3660357D1 (en) 1988-08-04
IN163199B (en) 1988-08-20

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