EP0808440A1 - Method and device for starting a continuous steam generator - Google Patents

Method and device for starting a continuous steam generator

Info

Publication number
EP0808440A1
EP0808440A1 EP96900860A EP96900860A EP0808440A1 EP 0808440 A1 EP0808440 A1 EP 0808440A1 EP 96900860 A EP96900860 A EP 96900860A EP 96900860 A EP96900860 A EP 96900860A EP 0808440 A1 EP0808440 A1 EP 0808440A1
Authority
EP
European Patent Office
Prior art keywords
evaporator
throughput
heat output
fuel
time
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP96900860A
Other languages
German (de)
French (fr)
Other versions
EP0808440B1 (en
Inventor
Joachim Franke
Eberhard Wittchow
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
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Filing date
Publication date
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B35/00—Control systems for steam boilers
    • F22B35/06—Control systems for steam boilers for steam boilers of forced-flow type
    • F22B35/14—Control systems for steam boilers for steam boilers of forced-flow type during the starting-up periods, i.e. during the periods between the lighting of the furnaces and the attainment of the normal operating temperature of the steam boilers

Definitions

  • the invention relates to a method for starting up a once-through steam generator with a combustion chamber having a number of burners for a fossil fuel, the gas-tight surrounding wall of which is formed from at least approximately vertically arranged evaporator tubes which pass through from the bottom upwards become. It further relates to an apparatus for performing the method.
  • a circulating stream is usually superimposed on the continuous flow of the evaporator of the continuous steam generator - and often also a flue gas-heated preheater or economizer arranged in the continuous steam generator - during start-up in order to cool it reliably by correspondingly high speeds in the pipes.
  • the minimum flow consisting of continuous flow and superimposed circulation flow in the case of vertically arranged pipes in the peripheral walls of the combustion chamber is between 25% and 50% of the full load flow. This means that during the start-up process the steam generator load must first be increased to at least 25% to 50% before the efficient continuous operation with its high steam outlet temperatures is achieved.
  • the amount of the flow medium to be delivered by a feed pump is therefore preferably kept constant for starting and in a load range below a certain limit load of 50% of the full load.
  • the feed flow of the feed pump is equal to the evaporator throughput.
  • the circulation circuit to be installed for the start-up process which usually comprises at least one circulation pump with appropriate accessories or a waste heat exchanger, is associated with a high level of technical complexity and therefore high investment costs required. These investment costs increase sharply with the realization of high and very high vapor pressures.
  • the invention is therefore based on the object of specifying a method and a device for operating a once-through steam generator with low start-up losses. This is to be achieved with little technical effort in a device suitable for carrying out the method.
  • this object is achieved according to the invention in that the evaporator throughput is set as a function of the quantity of fuel supplied to the or each burner per unit of time, the evaporator throughput rate proportional to the heat output in the combustion chamber.
  • the evaporator throughput i.e. the amount of the medium supplied to the evaporator and flowing through it is set within a narrow tolerance band in the procedure according to the invention.
  • the invention is based on the knowledge that a once-through steam generator can also be started up with a rapidly increasing firing rate, since its relatively thin-walled components allow high temperature change speeds. Due to the small storage mass of the evaporator, rapid steam formation occurs, as a result of which superheater heating surfaces provided for the superheating are well cooled.
  • the invention is based on the consideration that even with very low mass flow densities and at the same time high heat flow densities, there is very good heat transfer from a pipe wall to the flow medium if a so-called ring flow is formed.
  • Recent studies on the internal heat transfer in vertical pipes have surprisingly confirmed the formation of such a ring flow, even at very low mass flow densities, in which a large proportion of water in the flow medium formed by a water-water / steam mixture on the pipe wall is always present is transported. This also leads to the above-mentioned good heat transfer at a minimum current which is below about 25% of the full load flow, ie the evaporator throughput at 100% load.
  • the described thermal engineering phenomenon is implemented particularly favorably in the method for operating a once-through steam generator during start-up if, based on a minimum throughput of the evaporator of less than 15%, preferably less than 10%, e.g. 5% of the full-load throughput, the evaporator throughput deviates only in a narrow range from the percentage of the combustion heat output related to full-load.
  • the evaporator throughput is expediently limited to 5% to 10% of the full-load throughput. This ensures a uniform upward flow in all evaporator tubes right from the start.
  • the evaporator throughput is set in such a way that the percentage evaporator throughput based on the full load throughput is within a certain range equal to the percent of the combustion heat output based on full load.
  • the range is preferably between 3 to 8% above and between 2 to 3% below the percentage of the combustion heat output which increases over time. This condition of an asymmetrical bandwidth applies in particular to a combustion heat output in which a stable combustion is ensured.
  • the gas-tight surrounding wall of which is formed from at least approximately vertically arranged evaporator tubes through which the medium can flow from bottom to top solved by a controller module for setting the Amount of medium supplied to the evaporator per unit of time as a function of the quantity of fuel supplied to the or each burner per unit of time.
  • the controlled variable is expediently the evaporator throughput, i.e. the amount of feed water supplied to the evaporator on the medium side per time unit.
  • the controller module is therefore connected in an advantageous embodiment to an actuator connected to a feed water line leading into the evaporator and to a first flow sensor connected to the feed water line and to a second flow sensor connected to a or each burner fuel line.
  • the advantages achieved by the invention are, in particular, that the start-up losses decrease during a start-up process of a continuous steam generator due to an evenly increasing evaporator throughput with the thermal output of the furnace, since even with low load, an efficient continuous operation is achieved.
  • the circulation pumps or waste heat exchangers can advantageously be omitted, so that the investment costs are reduced and the system availability is increased.
  • FIG. 1 schematically shows a once-through steam generator with a vertical throttle cable and a start-up control device
  • Figure 2 is a start-up diagram for an evaporator throughput and a heat output.
  • the vertical throttle cable of the steam generator 1 according to FIG. 1 with a rectangular cross section is formed by a surrounding wall 2 which merges into a trihedral bottom 3 at the lower end of the gas cable.
  • Evaporator tube 4 of the surrounding wall 2 are connected gas-tightly on their long sides, e.g. welded.
  • the bottom 3 comprises a discharge opening 3a for ashes, not shown.
  • the lower region of the peripheral wall 2 forms the combustion chamber 6 of the continuous steam generator 1, which is provided with a number of burners 5.
  • the medium side, i.e. Evaporator tubes 4 of the surrounding wall 2 through which feed water or a water / water / steam mixture flows in parallel, from bottom to top, or one behind the other in the case of evaporator tube groups, are at their inlet ends to an inlet header 8 and at their outlet ends an outlet header 10 connected.
  • the inlet header 8 and the outlet header 10 are located outside the throttle cable and are e.g. each formed by an annular tube.
  • the inlet header 8 is connected via a line 12 and a header 14 to the outlet of a high-pressure preheater or economizer 15.
  • the heating surface of the economizer 15 is arranged in a space of the surrounding wall 2 above the combustion chamber 6.
  • the economizer 15 is connected on the input side via a collector 16 to a feed water tank 18, which is connected in a manner not shown to a steam turbine via a condenser and is therefore connected to its water-steam cycle.
  • the outlet header 10 is connected via a water-steam separation vessel 20 and a line 22 to a high-pressure superheater 24, which is arranged within the peripheral wall 2 between the economizer 15 and the combustion chamber 5.
  • the high-pressure superheater 24 is connected on the output side to a high-pressure part of the steam turbine via a collector 26 during operation. Between the high-pressure superheater 24 and the economizer 15, an intermediate superheater 28 is provided within the peripheral wall 2 and is connected via collectors 30, 32 between the high-pressure part and a medium-pressure part of the steam turbine.
  • a motor-operated feed water pump 34 and a heat exchanger 36 heated by steam D for feed water preheating, as well as a valve 38 and a flow sensor 40 are connected.
  • the flow sensor 40 is used to determine the amount of feed water S carried out per unit of time via the feed water line 17.
  • the amount of feed water S conducted per unit of time via the line 17 corresponds to the feed water quantity supplied from the evaporator tubes 4 and thus the evaporator throughput.
  • Another flow sensor 42 is connected to a fuel line 44, which opens into the burner 5 via sub-lines 46.
  • a valve 48 for adjusting the amount of fuel B supplied to the or each burner 5 per unit time is connected into the fuel line 44.
  • the flow sensors 40 and 42 are connected to a controller module 54 via signal lines 50 and 52 into which converters 51 and 53 are connected.
  • the controller module 54 is connected to the valve 38 via a line 56.
  • the regulator module 54 can alternatively also be connected to the motor-operated feed water pump 34 via a line 56 'shown in broken lines.
  • the controller block 54 and the Flow sensors 40, 42 and the valve 38 used to adjust the amount of feed water S are part of a control device 58 for starting the continuous steam generator 1.
  • the feed water pump 34 itself can also be changed by changing its speed to adjust the amount of the over Feed water line 17 guided feed water S can be used.
  • the control device 58 is used to adjust the evaporator throughput as a function of the amount of fuel supplied to the or each burner 5 per unit of time during a start-up process.
  • the controller module 54 is supplied with the current value of the quantity of the evaporator, i.e. the evaporator, via the signal line 50, measured by means of the flow sensor 40. the evaporator tubes 4, supplied per unit time of the feed water S.
  • This value supplied to the controller module 54 by the flow sensor 42 corresponds to the current evaporator throughput VD (FIG. 2).
  • the current value of the combustion heat output FW (FIG. 2) in the combustion chamber 6 is fed to the controller module 54 via the signal line 52.
  • the amount of the fuel B supplied to the burners 5 via the fuel line 44 at the current time is determined by means of the flow sensor 42.
  • This fuel throughput is converted by means of the converter 53 into the corresponding combustion heat output FW.
  • a control variable SG is determined in the control module 54 from a comparison of the current combustion heat output FW and the current evaporator throughput VD, which controls the valve 38 or the speed of the feed water pump 34 via line 56 or 56 '.
  • the amount of the feed water S fed via the feed water line 17 and thus the evaporator throughput VD is set proportionally to the combustion heat output FW in the combustion chamber 6, the evaporator throughput VD serving as a control variable.
  • the time-dependent course of the evaporator throughput VD and the combustion heat output FW is shown in FIG. 2. While the abscissa represents the time axis, percentages are plotted on the ordinate that relate to the maximum evaporator throughput (evaporator throughput at 100% load) and the maximum combustion heat output (combustion heat output at 100% load).
  • a minimum throughput of less than 15% of the throughput at 100% load is preferably already set.
  • this minimum throughput is within a bandwidth BD of 5% to 10% of the throughput at 100% load, i.e. the maximum Verdampfer ⁇ throughput VD.
  • This minimum throughput of 5% to 10% of the maximum evaporator throughput VD is set at the start of the start-up process.
  • the first burner 5 is ignited at a point in time, the firing heat output FW initially rising suddenly.
  • the combustion heat output FW initially increases in steps. From a furnace heat output FW of approximately 6% of the maximum furnace heat output, the furnace heat output FW increases continuously over time t. With the continuous increase in the combustion heat output FW, the evaporator throughput VD is also continuously increased.
  • the evaporator throughput VD is preferably set such that the percentage evaporator throughput VD related to the throughput at full load within the bandwidth BD of 5% to 10% of the throughput at full load is equal to the percentage firing heat output FW related to full load, ie 100% load .
  • the bandwidth BD within which the evaporator throughput VD increases with the combustion heat output FW over time, is limited by an upper limit line OG and a lower limit line UG.
  • the evaporator throughput VD is preferably set to increase in time with the combustion heat output FW during the start-up process.
  • the bandwidth BD - as can be seen in FIG.
  • the bandwidth BD is 5%, so that an upward deviation A 0 from the combustion heat output FW by 3% and a deviation A u from the combustion heat output FW downwards by 2% is permissible.
  • the amount of the feed water S supplied to the evaporator 4 per unit of time is therefore set by means of the control device 58 such that the evaporator throughput deviates from the percentage firing heat output FW only in a narrow range of preferably 5% to 10%. Even with a minimum throughput of less than 15%, i.e. Even if the evaporator throughput VD is limited to preferably 5% to 10% of the throughput at full load at the start of the start-up process, a uniform upward flow in all evaporator tubes 4 is ensured. Such a start-up behavior keeps start-up losses particularly low, since the low-load continuous operation is achieved with low efficiency.
  • Circulation pumps or waste heat exchangers that have been used up to now can be dispensed with in this start-up method.
  • water can be fed back into the feed water tank 18 and thus into the water-steam circuit directly via a return line 62, into which a valve 63 is connected, without additional pumps. Since there is therefore also a return of the feed water S from the water-steam separation vessel 20 in the direction of flow of the feed water S in front of the evaporator 4 or in front of the economizer 15 and thus behind the feed water container 18 can be dispensed with, a particularly simple regulation of the start-up process is achieved.

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

Abstract

The invention concerns a method of starting a continuous steam generator (1) comprising a combustion chamber (6) which comprises a plurality of burners (5) for a fossil fuel (B) and whose gastight outer wall (2) is formed from at least approximately vertically disposed evaporator tubes (4) through which the medium flows in an upward direction. In order to reduce losses on starting, the evaporator throughput (VD) is set in proportion to the firing heating capacity (FW) in the combustion chamber (6). To this end, a control arrangement (58) with a control module (54) is used for adjusting the amount of medium (S) fed to the evaporator (4) per unit of time as a function of the amount of fuel fed to the or each burner (5) per unit of time.

Description

Beschreibung description
Verfahren und Vorrichtung zum Anfahren eines Durchlaufdampf- erzeugersMethod and device for starting a continuous steam generator
Die Erfindung bezieht sich auf ein Verfahren zum Anfahren ei¬ nes Durchlaufdampferzeugers mit einer eine Anzahl von Bren¬ nern für einen fossilen Brennstoff aufweisenden Brennkammer, deren gasdichte Umfassungswand aus mindestens annähernd ver- tikal verlaufend angeordneten Verdampferrohren gebildet ist, die ediumseitig von unten nach oben durchsetzt werden. Sie bezieht sich weiter auf eine Vorrichtung zur Durchführung des Verfahrens.The invention relates to a method for starting up a once-through steam generator with a combustion chamber having a number of burners for a fossil fuel, the gas-tight surrounding wall of which is formed from at least approximately vertically arranged evaporator tubes which pass through from the bottom upwards become. It further relates to an apparatus for performing the method.
Während in einem Naturumlaufdampferzeuger ein im Umlauf ge¬ führtes Wasser-Wasserdampf-Gemisch nur teilweise verdampft, führt bei einem Durchlaufdampferzeuger die Beheizung von die gasdichten Umfassungswände einer Brennkammer bildenden verti¬ kal angeordneten Verdampferrohren zu einer vollständigen Ver- dampfung des Strömungsmediums in den Verdampferrohren in ei¬ nem Durchgang.While in a natural circulation steam generator a circulating water-water vapor mixture only partially evaporates, in a continuous steam generator the heating of vertically arranged evaporator tubes forming the gas-tight surrounding walls of a combustion chamber leads to complete evaporation of the flow medium in the evaporator tubes in egg ¬ a passage.
Üblicherweise wird dem Durchlaufström des Verdampfers des Durchlaufdampferzeugers - und häufig auch einem im Durchlauf- dampferzeuger angeordneten rauchgasbeheizten Vorwärmer oder Economizer - während des Anfahrens ein Umlaufstrom überla¬ gert, um durch entsprechend hohe Geschwindigkeiten in den Rohren diese sicher zu kühlen. Dabei beträgt der aus Durch¬ laufstrom und überlagertem Umlaufström bestehende Mindest- ström bei vertikal angeordneten Rohren in den Umfassungswän¬ den der Brennkammer zwischen 25 % und 50 % des Volllast¬ stroms. Dies bedeutet, daß beim Anfahrvorgang die Dampferzeu¬ gerlast erst auf mindestens 25 % bis 50 % gesteigert werden muß, bevor der wirkungsgradmäßig günstige Durchlaufbetrieb mit seinen hohen Dampfaustrittstemperaturen erreicht wird. Wie aus der europäischen Patentschrift 0 054 601 Bl bekannt ist, wird daher üblicherweise zum Anfahren und in einem unter einer bestimmten Grenzlast von 50 % der Vollast liegenden Lastbereich die Menge des von einer Speisepumpe zu fördernden Strömungsmediums vorzugsweise konstant gehalten. Dabei ist der Förderstrom der Speisepumpe gleich dem Verdampferdurch¬ satz. Bei dieser Betriebsweise sind die mit dem Zünden eines ersten Brenners des Durchlaufdampferzeugers beginnenden und mit Erreichen des Durchlaufbetriebs mit seinen hohen Dampf- temperaturen endenden Anfahrzeiten sehr lang. Dies hat ver¬ hältnismäßig hohe Anfahrverluste zur Folge, da deren Höhe we¬ sentlich von den Anfahrzeiten beeinflußt werden.A circulating stream is usually superimposed on the continuous flow of the evaporator of the continuous steam generator - and often also a flue gas-heated preheater or economizer arranged in the continuous steam generator - during start-up in order to cool it reliably by correspondingly high speeds in the pipes. The minimum flow consisting of continuous flow and superimposed circulation flow in the case of vertically arranged pipes in the peripheral walls of the combustion chamber is between 25% and 50% of the full load flow. This means that during the start-up process the steam generator load must first be increased to at least 25% to 50% before the efficient continuous operation with its high steam outlet temperatures is achieved. As is known from European patent specification 0 054 601 B1, the amount of the flow medium to be delivered by a feed pump is therefore preferably kept constant for starting and in a load range below a certain limit load of 50% of the full load. The feed flow of the feed pump is equal to the evaporator throughput. In this mode of operation, the start-up times which start with the ignition of a first burner of the once-through steam generator and end with the end of the once-through operation with its high steam temperatures are very long. This results in comparatively high start-up losses, since their amount is significantly influenced by the start-up times.
Im Zusammenhang mit den Bemühungen zur Steigerung des mittle- ren, auch den Anfahrvorgang umfassenden Wirkungsgrades einer Kraftwerksanlage, insbesondere durch Realisierung hoher und höchster Dampfzustände, kommt daher einer Reduzierung der An¬ fahrverluste erhöhte Bedeutung zu. Weiterhin ist bei einer derartigen Kraftwerksanlage zu beachten, daß der für den An- fahrvorgang zu installierende Umwälzkreislauf, der üblicher¬ weise mindestens eine Umwälzpumpe mit entsprechendem Zubehör oder einen Ablaufwärmetauscher umfaßt, mit einem hohen tech¬ nischen Aufwand verbunden ist und daher hohe Investitionsko¬ sten erfordert. Diese Investitionskosten nehmen mit der Rea- lisierung hoher und höchster Dampfdrücke stark zu.In connection with the efforts to increase the average efficiency of a power plant, which also includes the starting process, in particular by realizing high and highest steam conditions, a reduction in starting losses is therefore of greater importance. In such a power plant, it should also be noted that the circulation circuit to be installed for the start-up process, which usually comprises at least one circulation pump with appropriate accessories or a waste heat exchanger, is associated with a high level of technical complexity and therefore high investment costs required. These investment costs increase sharply with the realization of high and very high vapor pressures.
Der Erfindung liegt daher die Aufgabe zugrunde, ein Verfahren und eine Vorrichtung zum Betreiben eines Durchlaufdampferzeu¬ gers mit niedrigen Anfahrverlusten anzugeben. Dies soll bei einer zur Durchführung des Verfahrens geeigneten Vorrichtung mit geringem technischen Aufwand erreicht werden.The invention is therefore based on the object of specifying a method and a device for operating a once-through steam generator with low start-up losses. This is to be achieved with little technical effort in a device suitable for carrying out the method.
Bezüglich des Verfahrens wird diese Aufgabe erfindungsgemäß dadurch gelöst, daß der Verdampferdurchsatz in Abhängigkeit von der dem oder jedem Brenner pro Zeiteinheit zugeführten Brennstoffmenge eingestellt wird, wobei der Verdampferdurch- satz proportional zur Feuerwärmeleistung in der Brennkammer eingestellt wird.With regard to the method, this object is achieved according to the invention in that the evaporator throughput is set as a function of the quantity of fuel supplied to the or each burner per unit of time, the evaporator throughput rate proportional to the heat output in the combustion chamber.
Mit anderen Worten: Da die auf Vollast, d.h. auf 100 % Last, bezogene prozentuale Feuerungswärmeleistung als Ziel- oder Sollwert (setpoint) für den prozentualen Verdampferdurchsatz gewählt wird, wird der Verdampferdurchsatz, d.h. die Menge des dem Verdampfer pro Zeiteinheit zugeführten und diesen durchströmenden Mediums, bei erfindungsgemäßem Vorgehen in- nerhalb eines engen Toleranzbandes eingestellt.In other words, since the full load, i.e. based on 100% load, based on the percentage of the combustion heat output as the target or setpoint for the percentage evaporator throughput, the evaporator throughput, i.e. the amount of the medium supplied to the evaporator and flowing through it is set within a narrow tolerance band in the procedure according to the invention.
Die Erfindung geht dabei von der Erkenntnis aus, daß ein Durchlaufdampferzeuger auch mit einer schnell steigenden Feu¬ erleistung angefahren werden kann, da seine verhältnismäßig dünnwandigen Bauteile große Temperaturänderungsgeschwindig¬ keiten zulassen. Aufgrund der geringen Speichermasse des Ver¬ dampfers setzt eine rasche Dampfbildung ein, wodurch zur Oberhitzung erzeugten Dampfes vorgesehene Überhitzerheizflä¬ chen gut gekühlt werden.The invention is based on the knowledge that a once-through steam generator can also be started up with a rapidly increasing firing rate, since its relatively thin-walled components allow high temperature change speeds. Due to the small storage mass of the evaporator, rapid steam formation occurs, as a result of which superheater heating surfaces provided for the superheating are well cooled.
Den herkömmlichen Anfahr-Verfahren für Durchlaufdampferzeuger lag dabei die Annahme zugrunde, daß die Verdampferrohre der hochbeheizten Brennkammer nur dann gut gekühlt werden, wenn- die Mediumströmung in den Rohren turbulent ist, was eine ent- sprechend hohe Massenstromdichte in den Rohren auch während des Anfahrvorganges voraussetzt.The conventional start-up procedures for continuous steam generators were based on the assumption that the evaporator tubes of the highly heated combustion chamber are only well cooled if the medium flow in the tubes is turbulent, which also requires a correspondingly high mass flow density in the tubes during the start-up process .
Die Erfindung geht nun von der Überlegung aus, daß auch bei sehr niedrigen Massenstromdichten und zugleich hohen Wär e- stromdichten ein sehr guter Wärmeübergang von einer Rohrwand an das Strömungsmedium vorhanden ist, wenn sich eine soge¬ nannte Ringströmung ausbildet. Neuere Untersuchungen zum in¬ neren Wärmeübergang in vertikalen Rohren haben überraschen¬ derweise auch bei sehr niedrigen Massenstromdichten die Aus- bildung einer derartigen Ringströmung bestätigt, bei der stets ein großer Wasseranteil im durch ein Wasser-Wasser/ Dampf-Gemisch gebildeten Strömungsmedium an die Rohrwand transportiert wird. Dies führt auch bei einem unterhalb von etwa 25 % des Vollaststromes, d.h. des Verdampferdurchsatzes bei 100 % Last, liegenden Mindeststrom zu dem erwähnten guten Wärmeübergang.The invention is based on the consideration that even with very low mass flow densities and at the same time high heat flow densities, there is very good heat transfer from a pipe wall to the flow medium if a so-called ring flow is formed. Recent studies on the internal heat transfer in vertical pipes have surprisingly confirmed the formation of such a ring flow, even at very low mass flow densities, in which a large proportion of water in the flow medium formed by a water-water / steam mixture on the pipe wall is always present is transported. This also leads to the above-mentioned good heat transfer at a minimum current which is below about 25% of the full load flow, ie the evaporator throughput at 100% load.
Das beschriebene wärmetechnische Phänomen wird bei dem Ver¬ fahren zum Betreiben eines Durchlaufdampferzeugers während des Anfahrens insbesondere dann besonders günstig umgesetzt, wenn ausgehend von einem Mindestdurchsatz des Verdampfers von weniger als 15 %, vorzugsweise weniger als 10 %, z.B. 5 % des Vollastdurchsatzes der Verdampferdurchsatz nur in einer schmalen Bandbreite von der prozentualen, auf Vollast bezoge¬ nen Feuerungswärmeleistung abweicht.The described thermal engineering phenomenon is implemented particularly favorably in the method for operating a once-through steam generator during start-up if, based on a minimum throughput of the evaporator of less than 15%, preferably less than 10%, e.g. 5% of the full-load throughput, the evaporator throughput deviates only in a narrow range from the percentage of the combustion heat output related to full-load.
Zu Beginn des Anfahrvorgangs wird zweckmäßigerweise der Ver¬ dampferdurchsatz auf 5 % bis 10 % des Vollast-Durchsatzes be¬ grenzt. Dadurch ist von Anfang an eine gleichmäßige Aufwärts¬ strömung in allen Verdampferröhren gewährleistet . Nach dem Zünden des ersten Brenners wird der Verdampferdurchsatz der- art eingestellt, daß der auf den Vollast-Durchsatz bezogene prozentuale Verdampferdurchsatz innerhalb einer bestimmten Bandbreite gleich der auf Vollast bezogenen prozentualen Feuerungswärmeleistung ist. Dabei erstreckt sich die Band¬ breite vorzugsweise zwischen 3 bis 8 % oberhalb und zwischen 2 bis 3 % unterhalb der über die Zeit ansteigenden, prozen¬ tualen Feuerungswärmeleistung. Diese Bedingung einer asymme¬ trischen Bandbreite gilt insbesondere für eine Feuerungswär¬ meleistung, bei der eine stabile Verbrennung sichergestellt ist.At the start of the start-up process, the evaporator throughput is expediently limited to 5% to 10% of the full-load throughput. This ensures a uniform upward flow in all evaporator tubes right from the start. After the first burner has been ignited, the evaporator throughput is set in such a way that the percentage evaporator throughput based on the full load throughput is within a certain range equal to the percent of the combustion heat output based on full load. The range is preferably between 3 to 8% above and between 2 to 3% below the percentage of the combustion heat output which increases over time. This condition of an asymmetrical bandwidth applies in particular to a combustion heat output in which a stable combustion is ensured.
Bezüglich der Vorrichtung zum Anfahren eines Durchlaufdamp- ferzeugers mit einer eine Anzahl von Brennern für einen fos¬ silen Brennstoff aufweisenden Brennkammer, deren gasdichte Umfassungswand aus mindestens annähernd vertikal verlaufend angeordneten Verdampferrohren gebildet ist, die mediumsseitig von unten nach oben durchströmbar sind, wird die genannte Aufgabe gelöst durch einen Reglerbaustein zur Einstellung der Menge des dem Verdampfer pro Zeiteinheit zugeführten Mediums in Abhängigkeit von der dem oder jedem Brenner pro Zeitein¬ heit zugeführten Brennstoffmenge.With regard to the device for starting up a continuous-flow steam generator with a combustion chamber having a number of burners for a fossil fuel, the gas-tight surrounding wall of which is formed from at least approximately vertically arranged evaporator tubes through which the medium can flow from bottom to top solved by a controller module for setting the Amount of medium supplied to the evaporator per unit of time as a function of the quantity of fuel supplied to the or each burner per unit of time.
Die Regelgröße ist zweckmäßigerweise der Verdampferdurchsatz, d.h. die Menge der den Verdampfer mediumseitig pro Zeitein¬ heit zugeführten Speisewassers. Der Reglerbaustein ist daher in vorteilhafter Ausgestaltung verbunden mit .einem in eine in den Verdampfer führenden Speisewasserleitung geschalteten Stellglied und mit einem in die Speisewasserleitung geschal¬ teten ersten Durchflußmeßfühler sowie mit einem in eine an den oder jeden Brenner führenden Brennstoffleitung geschalte¬ ten zweiten Durchflußmeßfühler.The controlled variable is expediently the evaporator throughput, i.e. the amount of feed water supplied to the evaporator on the medium side per time unit. The controller module is therefore connected in an advantageous embodiment to an actuator connected to a feed water line leading into the evaporator and to a first flow sensor connected to the feed water line and to a second flow sensor connected to a or each burner fuel line.
Die mit der Erfindung erzielten Vorteile bestehen insbeson¬ dere darin, daß durch einen mit der Feuerungswärmeleistung gleichmäßig ansteigenden Verdampferdurchsatz während eines Anfahrvorgangs eines Durchlaufdampferzeugers die Anfahrver¬ luste sinken, da bereits bei niedriger Last ein wirkungsgrad- mäßig günstiger Durchlaufbetrieb erreicht wird. Dabei können vorteilhafterweise die Umwälzpumpen oder Ablaufwärmetauscher entfallen, so daß die Investitionskosten reduziert und die Anlagenverfügbarkeit erhöht sind.The advantages achieved by the invention are, in particular, that the start-up losses decrease during a start-up process of a continuous steam generator due to an evenly increasing evaporator throughput with the thermal output of the furnace, since even with low load, an efficient continuous operation is achieved. In this case, the circulation pumps or waste heat exchangers can advantageously be omitted, so that the investment costs are reduced and the system availability is increased.
Da auch eine Rückführung von abgeschiedenem Wasser aus einer dem Verdampfer nachgeschalteten Wasser-Dampf-Trenneinrichtung in eine Stelle zwischen Speisepumpe und Verdampfer entfällt, ist bei einer Schaltung ohne Umwälzpumpe die Einstellung des Anfahrvorgangs wesentlich vereinfacht. Dadurch werden Schwan- kungen der Enthalpie bei Eintritt des Wasserstroms in denSince there is also no return of separated water from a water-steam separator connected downstream of the evaporator to a point between the feed pump and the evaporator, the setting of the start-up process is considerably simplified in the case of a circuit without a circulation pump. As a result, fluctuations in the enthalpy when the water flow enters the
Verdampfer und damit auch Schwankungen des aus dem Verdampfer austretenden Wasserstroms vermieden.Evaporator and thus also fluctuations in the water flow emerging from the evaporator avoided.
Ein Ausführungsbeispiel der Erfindung wird anhand einer Zeichnung näher erläutert. Darin zeigen: Figur 1 schematisch einen Durchlaufdampferzeuger mit verti¬ kalem Gaszug und einer Anfahr-Regelvorrichtung, undAn embodiment of the invention is explained in more detail with reference to a drawing. In it show: 1 schematically shows a once-through steam generator with a vertical throttle cable and a start-up control device, and
Figur 2 ein Anfahr-Diagramm für einen Verdampferdurchsatz und eine Feuerwärmeleistung.Figure 2 is a start-up diagram for an evaporator throughput and a heat output.
Der vertikale Gaszug des Dampferzeugers 1 gemäß Figur 1 mit rechteckigem Querschnitt ist durch eine Umfassungswand 2 ge¬ bildet, die am Unterende des Gaszugs in einen triehterförmi- gen Boden 3 übergeht. Verdampferröhre 4 der Umfassungswand 2 sind an ihren Längsseiten gasdicht miteinander verbunden, z.B. verschweißt. Der Boden 3 umfaßt eine nicht näher darge¬ stellte Austragsöffnung 3a für Asche.The vertical throttle cable of the steam generator 1 according to FIG. 1 with a rectangular cross section is formed by a surrounding wall 2 which merges into a trihedral bottom 3 at the lower end of the gas cable. Evaporator tube 4 of the surrounding wall 2 are connected gas-tightly on their long sides, e.g. welded. The bottom 3 comprises a discharge opening 3a for ashes, not shown.
Der untere Bereich der Umfassungswand 2 bildet die mit einer Anzahl von Brennern 5 versehene Brennkammer 6 des Durchlauf- dampferzeugers 1.The lower region of the peripheral wall 2 forms the combustion chamber 6 of the continuous steam generator 1, which is provided with a number of burners 5.
Die mediumseitig, d.h. von Speisewasser oder einem Was- ser/Wasser-Dampf-Gemisch, von unten nach oben parallel - oder bei Verdampferrohrgruppen hintereinander - durchströmten Ver¬ dampferrohre 4 der Umfassungswand 2 sind mit ihren Eintritts¬ enden an einen Eintrittssammler 8 und mit ihren Austrittsen¬ den an einen Austrittssammler 10 angeschlossen. Der Ein- trittssammler 8 und der Austrittssammler 10 befinden sich außerhalb des Gaszugs und sind z.B. jeweils durch ein ring¬ förmiges Rohr gebildet.The medium side, i.e. Evaporator tubes 4 of the surrounding wall 2 through which feed water or a water / water / steam mixture flows in parallel, from bottom to top, or one behind the other in the case of evaporator tube groups, are at their inlet ends to an inlet header 8 and at their outlet ends an outlet header 10 connected. The inlet header 8 and the outlet header 10 are located outside the throttle cable and are e.g. each formed by an annular tube.
Der Eintrittssammler 8 ist über eine Leitung 12 und einen Sammler 14 mit dem Ausgang eines Hochdruck-Vorwärmers oder Economizers 15 verbunden. Die Heizfläche des Economizers 15 ist in einem oberhalb der Brennkammer 6 liegenden Raum der Umfassungswand 2 angeordnet. Der Economizer 15 ist eingangs- seitig über einen Sammler 16 mit einem Speisewasserbehälter 18 verbunden, der in nicht näher dargestellter Art und Weise über einen Kondensator mit einer Dampfturbine verbunden und somit in deren Wasser-Dampf-Kreislauf geschaltet ist. Der Austrittssammler 10 ist über ein Wasser-Dampf-Trenngefäß 20 und eine Leitung 22 mit einem Hochdruck-Überhitzer 24 ver¬ bunden, der innerhalb der Umfassungswand 2 zwischen dem Eco- nomizer 15 und der Brennkammer 5 angeordnet ist. Der Hoch- druck-Überhitzer 24 ist während des Betriebs ausgangsseitig über einen Sammler 26 mit einem Hochdruckteil der Dampftur¬ bine verbunden. Zwischen dem Hochdruck-Überhitzer 24 und dem Economizer 15 ist innerhalb der Umfassungswand 2 ein Zwi¬ schenüberhitzer 28 vorgesehen, der über Sammler 30, 32 zwi- sehen dem Hochdruckteil und einem Mitteldruckteil der Dampf¬ turbine geschaltet ist.The inlet header 8 is connected via a line 12 and a header 14 to the outlet of a high-pressure preheater or economizer 15. The heating surface of the economizer 15 is arranged in a space of the surrounding wall 2 above the combustion chamber 6. The economizer 15 is connected on the input side via a collector 16 to a feed water tank 18, which is connected in a manner not shown to a steam turbine via a condenser and is therefore connected to its water-steam cycle. The outlet header 10 is connected via a water-steam separation vessel 20 and a line 22 to a high-pressure superheater 24, which is arranged within the peripheral wall 2 between the economizer 15 and the combustion chamber 5. The high-pressure superheater 24 is connected on the output side to a high-pressure part of the steam turbine via a collector 26 during operation. Between the high-pressure superheater 24 and the economizer 15, an intermediate superheater 28 is provided within the peripheral wall 2 and is connected via collectors 30, 32 between the high-pressure part and a medium-pressure part of the steam turbine.
In die Speisewasserleitung 17 sind in Strömungsrichtung des Speisewassers S aus dem Speisewasserbehälter 18 hintereinan- der eine motorbetriebene Speisewasserpumpe 34 und ein mittels Dampf D beheizter Wärmetauscher 36 zur Speisewasservorwärmung sowie ein Ventil 38 und ein Durchflußmeßfühler 40 geschaltet. Der Durchflußmeßfühler 40 dient zur Ermittlung der pro Zeit¬ einheit über die Speisewasserleitung 17 geführten Menge an Speisewasser S. Die pro Zeiteinheit über die Leitung 17 ge¬ führte Menge des Speisewassers S entspricht der dem aus den Verdampferröhren 4 bestehenden Verdampfer zugeführten Speise¬ wassermenge und somit dem Verdampferdurchsatz.In the feed water line 17 in the flow direction of the feed water S from the feed water tank 18, a motor-operated feed water pump 34 and a heat exchanger 36 heated by steam D for feed water preheating, as well as a valve 38 and a flow sensor 40 are connected. The flow sensor 40 is used to determine the amount of feed water S carried out per unit of time via the feed water line 17. The amount of feed water S conducted per unit of time via the line 17 corresponds to the feed water quantity supplied from the evaporator tubes 4 and thus the evaporator throughput.
Ein weiterer Durchflußmeßfühler 42 ist in eine Brennstofflei- tung 44 geschaltet, die über Teilleitungen 46 in die Brenner 5 mündet. In die Brennstoffleitung 44 ist ein Ventil 48 zur Einstellung der dem oder jedem Brenner 5 pro Zeiteinheit zu¬ geführten Menge an Brennstoff B geschaltet.Another flow sensor 42 is connected to a fuel line 44, which opens into the burner 5 via sub-lines 46. A valve 48 for adjusting the amount of fuel B supplied to the or each burner 5 per unit time is connected into the fuel line 44.
Die Durchflußmeßfühler 40 und 42 sind über Signalleitungen 50 und 52, in die Wandler 51 bzw. 53 geschaltet sind, mit einem Reglerbaustein 54 verbunden. Der Reglerbaustein 54 ist über eine Leitung 56 mit dem Ventil 38 verbunden. Der Reglerbau- stein 54 kann alternativ auch über eine gestrichelt darge¬ stellte Leitung 56' mit der motorbetriebenen Speisewasser¬ pumpe 34 verbunden sein. Der Reglerbaustein 54 und die Durch- flußmeßfühler 40, 42 sowie das zur Einstellung der Menge des Speisewassers S dienende Ventil 38 sind Bestandteil einer Re¬ gelvorrichtung 58 zum Anfahren des Durchlaufdampferzeugers 1. Anstelle des Ventils 38 kann auch die Speisewasserpumpe 34 selbst durch Veränderung ihrer Drehzahl zur Einstellung der Menge des über die Speisewasserleitung 17 geführten Speise¬ wassers S herangezogen werden.The flow sensors 40 and 42 are connected to a controller module 54 via signal lines 50 and 52 into which converters 51 and 53 are connected. The controller module 54 is connected to the valve 38 via a line 56. The regulator module 54 can alternatively also be connected to the motor-operated feed water pump 34 via a line 56 'shown in broken lines. The controller block 54 and the Flow sensors 40, 42 and the valve 38 used to adjust the amount of feed water S are part of a control device 58 for starting the continuous steam generator 1. Instead of the valve 38, the feed water pump 34 itself can also be changed by changing its speed to adjust the amount of the over Feed water line 17 guided feed water S can be used.
Die Regelvorrichtung 58 dient zur Einstellung des Verdampfer- durchsatzes in Abhängigkeit von der dem oder jedem Brenner 5 pro Zeiteinheit zugeführten Brennstoffmenge während eines An¬ fahrvorgangs. Dazu wird dem Reglerbaustein 54 über die Si¬ gnalleitung 50 der mittels des Durchflußmeßfühlers 40 gemes¬ sene aktuelle Wert der Menge des dem Verdampfer, d.h. den Verdampferröhren 4, pro Zeiteinheit zugeführten Menge des Speisewassers S zugeführt. Dieser dem Reglerbaustein 54 von dem Durchflußmeßfühler 42 zugeführte Wert entspricht dem ak¬ tuellen Verdampferdurchsatz VD (Figur 2). Außerdem wird dem Reglerbaustein 54 über die Signalleitung 52 der aktuelle Wert der Feuerungswärmeleistung FW (Figur 2) in der Brennkammer 6 zugeführt. Dazu wird mittels des Durchflußmeßfühlers 42 die Menge des den Brennern 5 über die Brennstoffleitung 44 zum aktuellen Zeitpunkt zugeführten Brennstoffs B ermittelt. Die¬ ser Brennstoffdurchsatz wird mittels des Wandlers 53 in die entsprechende Feuerungswärmeleistung FW umgewandelt. Im Reg¬ lerbaustein 54 wird aus einem Vergleich der aktuellen Feue¬ rungswärmeleistung FW und des aktuellen Verdampferdurchsatzes VD eine Stellgröße SG ermittelt, die über die Leitung 56 oder 56' das Ventil 38 bzw. die Drehzahl der Speisewasserpumpe 34 steuert. Dabei wird die Menge des über die Speisewasserlei¬ tung 17 geführten Speisewassers S und damit der Verdampfer¬ durchsatz VD proportional zur Feuerungswärmeleistung FW in der Brennkammer 6 eingestellt, wobei der Verdampferdurchsatz VD als Regelgröße dient.The control device 58 is used to adjust the evaporator throughput as a function of the amount of fuel supplied to the or each burner 5 per unit of time during a start-up process. For this purpose, the controller module 54 is supplied with the current value of the quantity of the evaporator, i.e. the evaporator, via the signal line 50, measured by means of the flow sensor 40. the evaporator tubes 4, supplied per unit time of the feed water S. This value supplied to the controller module 54 by the flow sensor 42 corresponds to the current evaporator throughput VD (FIG. 2). In addition, the current value of the combustion heat output FW (FIG. 2) in the combustion chamber 6 is fed to the controller module 54 via the signal line 52. For this purpose, the amount of the fuel B supplied to the burners 5 via the fuel line 44 at the current time is determined by means of the flow sensor 42. This fuel throughput is converted by means of the converter 53 into the corresponding combustion heat output FW. A control variable SG is determined in the control module 54 from a comparison of the current combustion heat output FW and the current evaporator throughput VD, which controls the valve 38 or the speed of the feed water pump 34 via line 56 or 56 '. The amount of the feed water S fed via the feed water line 17 and thus the evaporator throughput VD is set proportionally to the combustion heat output FW in the combustion chamber 6, the evaporator throughput VD serving as a control variable.
Der zeitabhängige Verlauf des Verdampferdurchsatzes VD und der Feuerungswärmeleistung FW ist in Figur 2 dargestellt. Während die Abszisse die Zeitachse darstellt, sind auf der Ordinate Prozentzahlen aufgetragen, die auf den maximalen Verdampferdurchsatz (Verdampferdurchsatz bei 100 % Last) und auf die maximale Feuerungswärmeleistung (Feuerungswärmelei- stung bei 100 % Last) bezogen sind.The time-dependent course of the evaporator throughput VD and the combustion heat output FW is shown in FIG. 2. While the abscissa represents the time axis, percentages are plotted on the ordinate that relate to the maximum evaporator throughput (evaporator throughput at 100% load) and the maximum combustion heat output (combustion heat output at 100% load).
Zum Zeitpunkt tQ, d.h. vor dem Zünden eines ersten Brenners 5, wird vorzugsweise bereits ein Mindestdurchsatz von weniger als 15 % des Durchsatzes bei 100 % Last (Vollastdurchsatz) eingestellt. Im Ausführungsbeispiel liegt dieser Mindest¬ durchsatz innerhalb einer Bandbreite BD von 5 % bis 10 % des Durchsatzes bei 100 % Last, d.h. des maximalen Verdampfer¬ durchsatzes VD. Dieser Mindestdurchsatz von 5 % bis 10 % des maximalen Verdampferdurchsatzes VD wird zu Beginn des Anfahr- Vorgangs eingestellt.At time tQ, i.e. before igniting a first burner 5, a minimum throughput of less than 15% of the throughput at 100% load (full load throughput) is preferably already set. In the exemplary embodiment, this minimum throughput is within a bandwidth BD of 5% to 10% of the throughput at 100% load, i.e. the maximum Verdampfer¬ throughput VD. This minimum throughput of 5% to 10% of the maximum evaporator throughput VD is set at the start of the start-up process.
Während des Vorgangs wird zu einem Zeitpunkt der erste Brenner 5 gezündet, wobei die Feuerungswärmeleistung FW zu¬ nächst sprunghaft ansteigt. Durch Zünden eines zweiten Bren- ners 5 zum Zeitpunkt t2 und eines dritten Brenners 5 zum Zeitpunkt t3 steigt die Feuerungswärmeleistung FW zunächst stufenweise an. Ab einer Feuerungswärmeleistung FW von etwa 6 % der maximalen Feuerungswärmeleistung steigt die Feue¬ rungswärmeleistung FW kontinuierlich über die Zeit t an. Mit dem kontinuierlichen Anstieg der Feuerungswärmeleistung FW wird auch der Verdampferdurchsatz VD kontinuierlich erhöht. Dabei wird der Verdampferdurchsatz VD vorzugsweise derart eingestellt, daß der auf den Durchsatz bei Vollast bezogene prozentuale Verdampferdurchsatz VD innerhalb der Bandbreite BD von 5 % bis 10 % des Durchsatzes bei Vollast gleich der auf Vollast, d.h. auf 100 % Last, bezogenen prozentualen Feuerungswärmeleistung FW ist. Die Bandbreite BD, innerhalb der der Verdampferdurchsatz VD mit der Feuerungswärmeleistung FW über die Zeit ansteigt, ist nach oben begrenzt durch eine obere Grenzlinie OG und nach unten durch eine untere Grenzli¬ nie UG. Vorzugsweise wird der Verdampferdurchsatz VD während des An¬ fahrvorgangs gleichmäßig mit der Feuerungswärmeleistung FW zeitlich ansteigend eingestellt. Dabei ist die Bandbreite BD - wie aus der Figur 2 ersichtlich - asymmetrisch, wobei eine Abweichung des prozentualen Verdampferdurchsatzes VD von der prozentualen Feuerungswärmeleistung nach oben um 3 % bis 8 % und nach unten um 2 % bis 3 % des Durchsatzes bei 100 % Last zulässig ist. Die Bandbreite BD beträgt im Ausführungsbei- spiel 5 %, so daß eine Abweichung A0 von der Feuerungswärme- leistung FW nach oben um 3 % und eine Abweichung Au von der Feuerungswärmeleistung FW nach unten um 2 % zulässig ist.During the process, the first burner 5 is ignited at a point in time, the firing heat output FW initially rising suddenly. By igniting a second burner 5 at time t2 and a third burner 5 at time t3, the combustion heat output FW initially increases in steps. From a furnace heat output FW of approximately 6% of the maximum furnace heat output, the furnace heat output FW increases continuously over time t. With the continuous increase in the combustion heat output FW, the evaporator throughput VD is also continuously increased. In this case, the evaporator throughput VD is preferably set such that the percentage evaporator throughput VD related to the throughput at full load within the bandwidth BD of 5% to 10% of the throughput at full load is equal to the percentage firing heat output FW related to full load, ie 100% load . The bandwidth BD, within which the evaporator throughput VD increases with the combustion heat output FW over time, is limited by an upper limit line OG and a lower limit line UG. The evaporator throughput VD is preferably set to increase in time with the combustion heat output FW during the start-up process. The bandwidth BD - as can be seen in FIG. 2 - is asymmetrical, a deviation of the percentage evaporator throughput VD from the percentage combustion heat output upwards by 3% to 8% and downwards by 2% to 3% of the throughput at 100% load is permissible is. In the exemplary embodiment, the bandwidth BD is 5%, so that an upward deviation A 0 from the combustion heat output FW by 3% and a deviation A u from the combustion heat output FW downwards by 2% is permissible.
Mittels der Regelvorrichtung 58 wird daher die Menge des dem Verdampfer 4 pro Zeiteinheit zugeführten Speisewassers S der- art eingestellt, daß der Verdampferdurchsatz nur in einer schmalen Bandbreite von vorzugsweise 5 % bis 10 % von der prozentualen Feuerungswärmeleistung FW abweich . Schon bei einem Mindestdurchsatz von weniger als 15 %, d.h. auch bei einer Begrenzung des Verdampferdurchsatzes VD zu Beginn des Anfahrvorgangs auf vorzugsweise 5 % bis 10 % des Durchsatzes bei Vollast wird eine gleichmäßige Aufwärtsströmung in allen Verdampferrohren 4 gewährleistet. Durch ein solches Anfahr- Verhalten werden Anfahrverluste besonders gering gehalten, da bereits bei niedriger Last der wirkungsgradmäßig günstige Durchlaufbetrieb erreicht wird.The amount of the feed water S supplied to the evaporator 4 per unit of time is therefore set by means of the control device 58 such that the evaporator throughput deviates from the percentage firing heat output FW only in a narrow range of preferably 5% to 10%. Even with a minimum throughput of less than 15%, i.e. Even if the evaporator throughput VD is limited to preferably 5% to 10% of the throughput at full load at the start of the start-up process, a uniform upward flow in all evaporator tubes 4 is ensured. Such a start-up behavior keeps start-up losses particularly low, since the low-load continuous operation is achieved with low efficiency.
Bisher üblicherweise eingesetzte Umwälzpumpen oder Ablaufwär¬ metauscher können bei diesem Anfahr-Verfahren entfallen. In dem in Figur 1 dargestellten Wasser-Dampf-Trenngefäß 20 abge- trenntes Wasser kann ohne zusätzliche Pumpen direkt über eine Rückführleitung 62, in die ein Ventil 63 geschaltet ist, in den Speisewasserbehälter 18 und damit in den Wasser-Dampf- Kreislauf zurückgeführt werden. Da somit auch eine Rückfüh¬ rung des Speisewassers S aus dem Wasser-Dampf-Trenngefäß 20 in Strömungsriehtung des Speisewassers S vor den Verdampfer 4 oder vor den Economizer 15 und damit hinter den Speisewasser- behälter 18 entfallen kann, wird eine besonders einfache Re¬ gelung des Anfahr-Vorgangs erreicht. Circulation pumps or waste heat exchangers that have been used up to now can be dispensed with in this start-up method. In the water-steam separating vessel 20 shown in FIG. 1, water can be fed back into the feed water tank 18 and thus into the water-steam circuit directly via a return line 62, into which a valve 63 is connected, without additional pumps. Since there is therefore also a return of the feed water S from the water-steam separation vessel 20 in the direction of flow of the feed water S in front of the evaporator 4 or in front of the economizer 15 and thus behind the feed water container 18 can be dispensed with, a particularly simple regulation of the start-up process is achieved.

Claims

Patentansprüche claims
1. Verfahren zum Anfahren eines Durchlaufdampferzeugers mit einer eine Anzahl von Brennern (5) für einen fossilen Brenn- stoff (B) aufweisenden Brennkammer (6) , deren gasdichte Um¬ fassungswand (2) aus mindestens annähernd vertikal verlaufend angeordneten Verdampferrohren (4) gebildet ist, die mediums¬ seitig von unten nach oben durchsetzt werden, d a d u r c h g e k e n n z e i c h n e t , daß der Ver- dampferdurchsatz (VD) in Abhängigkeit von der dem oder jedem Brenner (5) pro Zeiteinheit zugeführten Brennstoffmenge ein¬ gestellt wird, wobei der Verdampferdurchsatz (VD) proportio¬ nal zur Feuerwärmeleistung (FW) in der Brennkammer (6) einge¬ stellt wird.1. Method for starting up a continuous steam generator with a combustion chamber (6) having a number of burners (5) for a fossil fuel (B), the gas-tight surrounding wall (2) of which consists of evaporator tubes (4) arranged at least approximately vertically , which are penetrated from the bottom upwards on the medium side, characterized in that the evaporator throughput (VD) is set as a function of the quantity of fuel supplied to the or each burner (5) per unit of time, the evaporator throughput (VD) being proportional ¬ nal to the heat output (FW) in the combustion chamber (6) is set.
2. Verfahren nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t , daß zu Beginn des Anfahrvorgangs ein Mindestdurchsatz des Verdampfers (4) von weniger als 15 %, vorzugsweise weniger als 10 %, des Durchsatzes bei 100 % Last (Vollast-Durchsatz) eingestellt wird.2. The method according to claim 1, so that a minimum throughput of the evaporator (4) of less than 15%, preferably less than 10%, of the throughput at 100% load (full-load throughput) is set at the start of the start-up process.
3. Verfahren nach Anspruch 1 oder 2, d a d u r c h g e k e n n z e i c h n e t , daß der Ver- dampferdurchsatz (VD) gleichmäßig mit der Feuerungswärmelei¬ stung (FW) zeitlich ansteigend eingestellt wird.3. The method according to claim 1 or 2, so that the evaporator throughput (VD) is adjusted uniformly with the combustion heat output (FW) with increasing time.
4. Verfahren nach einem der Ansprüche 1 bis 3 d a d u r c h g e k e n n z e i c h n e t , daß der Ver- dampferdurchsatz (VD) derart eingestellt wird, daß der auf den Vollast-Durchsatz bezogene prozentuale Verdampferdurch¬ satz (VD) innerhalb einer Bandbreite (BD) gleich der auf Vollast bezogenen prozentualen Feuerungswärmeleistung (FW) is .4. The method according to any one of claims 1 to 3, characterized in that the evaporator throughput (VD) is set such that the percentage evaporator throughput (VD) related to the full load throughput within a bandwidth (BD) equal to that related to full load percentage firing thermal output (FW) is.
5. Verfahren nach Anspruch 4, d a d u r c h g e k e n n z e i c h n e t , daß die Band- breite (BD) asymmetrisch ist, wobei eine Abweichung (A0, Au) des prozentualen Verdampferdurchsatzes (VD) von der prozen¬ tualen Feuerwärmeleistung (FW) nach oben um 3 % bis 8 % und nach unten um 2 % bis 3 % des Vollast-Durchsatzes zulässig ist.5. The method according to claim 4, characterized in that the tape width (BD) is asymmetrical, with a deviation (A 0 , A u ) of the percent evaporator throughput (VD) from the percent heat output (FW) upwards by 3% to 8% and downwards by 2% to 3% of the Full load throughput is permitted.
6. Vorrichtung zum Anfahren eines Durchlaufdampferzeugers mit einer eine Anzahl von Brennern (5) für einen fossilen Brenn¬ stoff (B) aufweisenden Brennkammer (6), deren gasdichte Um- fassungswand (2) aus mindestens annähernd vertikal verlaufend angeordneten Verdampferrohren (4) gebildet ist, die mediums¬ seitig von unten nach oben durchströmbar sind, g e k e n n z e i c h n e t d u r c h einen Reglerbau¬ stein (54) zur Einstellung der Menge des dem Verdampfer (4) pro Zeiteinheit zugeführten Mediums (S) in Abhängigkeit von der dem oder jedem Brenner (5) pro Zeiteinheit zugeführten Brennstoffmenge.6. Device for starting a once-through steam generator with a combustion chamber (6) having a number of burners (5) for a fossil fuel (B), the gas-tight surrounding wall (2) of which consists of evaporator tubes (4) arranged at least approximately vertically which can be flowed through from the bottom upwards on the medium side, characterized by a controller module (54) for setting the amount of medium (S) supplied to the evaporator (4) per unit of time depending on the or each burner (5) Unit of time supplied amount of fuel.
7. Vorrichtung nach Anspruch 6, d a d u r c h g e k e n n z e i c h n e t , daß der Reg¬ lerbaustein (54) verbunden ist mit einem in eine in den Ver¬ dampfer (4) führenden Speisewasserleitung (17) geschalteten Stellglied (34, 38) und mit einem in die Speisewasserleitung (17) geschalteten ersten Durchflußmeßfühler (40) sowie mit einem in eine an den oder jeden Brenner führenden Brennstoff- leitung (44) geschalteten zweiten Durchflußmeßfühler (42) . 7. The device according to claim 6, characterized in that the regulator module (54) is connected to an actuator (34, 38) connected to a feed water line (17) leading into the evaporator (4) and to a feed water line ( 17) connected first flow sensor (40) and with a second flow sensor (42) connected to a fuel line (44) leading to the or each burner.
EP96900860A 1995-02-09 1996-01-29 Method and device for starting a once-through steam generator Expired - Lifetime EP0808440B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19504308A DE19504308C1 (en) 1995-02-09 1995-02-09 Method and device for starting a once-through steam generator
DE19504308 1995-02-09
PCT/DE1996/000115 WO1996024803A1 (en) 1995-02-09 1996-01-29 Method and device for starting a continuous steam generator

Publications (2)

Publication Number Publication Date
EP0808440A1 true EP0808440A1 (en) 1997-11-26
EP0808440B1 EP0808440B1 (en) 1999-08-18

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EP (1) EP0808440B1 (en)
JP (1) JP3836139B2 (en)
KR (1) KR100427125B1 (en)
CN (1) CN1119554C (en)
CA (1) CA2212517C (en)
DE (2) DE19504308C1 (en)
IN (1) IN186814B (en)
WO (1) WO1996024803A1 (en)

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DE19717158C2 (en) * 1997-04-23 1999-11-11 Siemens Ag Continuous steam generator and method for starting up a continuous steam generator
DE19907451A1 (en) * 1999-02-22 2000-08-24 Abb Alstom Power Ch Ag Method for starting a once-through waste heat boiler and device for carrying out the method
EP2065641A3 (en) * 2007-11-28 2010-06-09 Siemens Aktiengesellschaft Method for operating a continuous flow steam generator and once-through steam generator
EP2119880A1 (en) * 2008-02-15 2009-11-18 Siemens Aktiengesellschaft Method for starting a steam producer
EP2182278A1 (en) * 2008-09-09 2010-05-05 Siemens Aktiengesellschaft Continuous-flow steam generator
EP2180250A1 (en) * 2008-09-09 2010-04-28 Siemens Aktiengesellschaft Continuous-flow steam generator
US9541282B2 (en) * 2014-03-10 2017-01-10 International Paper Company Boiler system controlling fuel to a furnace based on temperature of a structure in a superheater section
DE102014222682A1 (en) 2014-11-06 2016-05-12 Siemens Aktiengesellschaft Control method for operating a continuous steam generator
DE102017205382A1 (en) * 2017-03-30 2018-10-04 Siemens Aktiengesellschaft Water return in vertical forced-circulation steam generators
CN110006025A (en) * 2019-03-19 2019-07-12 广东美智智能科技有限公司 A kind of boiler pressure regulation method, equipment and storage medium based on PID

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CH632331A5 (en) * 1978-10-03 1982-09-30 Sulzer Ag METHOD FOR STARTING A FORCED STEAM GENERATOR.
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Publication number Publication date
WO1996024803A1 (en) 1996-08-15
DE59602799D1 (en) 1999-09-23
DE19504308C1 (en) 1996-08-08
KR19980702020A (en) 1998-07-15
US5839396A (en) 1998-11-24
EP0808440B1 (en) 1999-08-18
CN1119554C (en) 2003-08-27
JP3836139B2 (en) 2006-10-18
CA2212517C (en) 2001-04-10
KR100427125B1 (en) 2004-08-02
CN1168172A (en) 1997-12-17
CA2212517A1 (en) 1996-08-15
IN186814B (en) 2001-11-17
JPH10513543A (en) 1998-12-22

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