EP0977964A1

EP0977964A1 - Continuous-flow steam generator and method for starting same

Info

Publication number: EP0977964A1
Application number: EP98931919A
Authority: EP
Inventors: Eberhard Wittchow
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1997-04-23
Filing date: 1998-04-14
Publication date: 2000-02-09
Anticipated expiration: 2018-04-14
Also published as: DE19717158C2; KR20010012074A; DE59805320D1; WO1998048217A1; RU2188357C2; CA2287177A1; CN1249807A; DE19717158A1; KR100543383B1; US6192837B1; DK0977964T3; CN1126905C; EP0977964B1

Abstract

The invention relates to a continuous-flow steam generator (1) designed in a two-pass construction style. A second gas pass (14) is connected downstream from a first gas pass (8) on the side of the heating gas via a horizontal gas pass (12). In a steam generator (1) of this kind, which should have a particularly long service life even if it is frequently started, a number of parallel-connected steam generating pipes (16) for a fluid medium to flow through are interconnected giving an evaporator heating surface (22) which is part of an encompassing wall (6) of the first gas pass (8). The steam-generating pipes (16) forming the evaporator heating surface (22) discharge on the output side into a common outlet collector (24) which is fitted at low height in relation to an under edge (44) of the horizontal gas pass (12). A bulkhead heating surface (26) is connected downstream from the outlet collector (24), on the side of the fluid medium.

Description

description

Continuous steam generator and method for starting up a continuous steam generator

The invention relates to a once-through steam generator according to the preamble of claim 1. Such a steam generator is known from EP 0 308 728 AI.

In a once-through steam generator, the heating of a number of evaporator tubes, which together form the gas-tight peripheral wall of a combustion chamber, leads to complete evaporation of the flow medium in the evaporator tubes in one pass. After its evaporation, the flow medium - usually water - is fed to the superheater tubes connected downstream of the evaporator tubes and overheated there. In contrast to a natural circulation steam generator, a continuous steam generator is not subject to any pressure limitation, so that fresh steam pressures well above the critical pressure of water (p _crit = 221 bar) - where there is only a slight difference in density between liquid-like and steam-like medium - are possible. A high live steam pressure favors high thermal efficiency and thus low C0 ₂ emissions from a fossil-fired power plant.

Such a continuous steam generator can be designed as a single-pass or double-pass design. In the case of a continuous-type steam generator of the draft type, steam generator pipes are usually welded together in a gas-tight manner to form the peripheral wall of a single gas train, the gas train being arranged vertically. The steam generator tubes forming the peripheral wall of the gas train generally include both evaporator tubes and superheater tubes connected downstream of these on the fluid side. A combustion chamber with a number of burners for fossil fuel is usually provided in a lower area of the gas train. In the case of a continuous steam generator of two-pass design, steam generator pipes are usually also welded to one another in a gas-tight manner to form the peripheral wall of a vertically arranged first gas train. In this design, however, the first gas flue is followed by a second vertically arranged gas flue on the hot gas side via a horizontal gas flue, the peripheral wall of which is also formed by steam generator tubes and through which the heating gas usually flows from top to bottom. A continuous steam generator in a two-pass design usually has a lower overall height in comparison to a pass-through steam generator in a pull-in type and differs from this in a number of design parameters.

In a continuous-flow steam generator of two-pass design, the steam generator pipes forming the peripheral wall of the first gas train are usually designed as evaporator pipes, whereas steam generator pipes designed as superheater pipes are part of the peripheral wall of the second gas train and / or part of a wall heating surface of the horizontal gas train. In other words: the steam generator pipes assigned to the horizontal gas train and the second gas train are usually connected downstream of the steam generator pipes assigned to the first gas train on the flow medium side. For this purpose, the steam generator tubes assigned to the first gas train open out on the output side into an outlet collector common to them, which is followed by an inlet collector for the steam generator tubes assigned to the second gas train via a water-steam separation device and a number of heating surfaces arranged in the horizontal gas train.

In the continuous steam generator known from EP 0 308 728 A1, a number of steam generator tubes connected in parallel for the flow of a flow medium are connected to one another to form an evaporator heating surface which is part of a peripheral wall of the first gas flue. The steam generator tubes forming the evaporator heating surface open out on the output side into a common outlet manifold, which is lower than the bottom edge of the horizontal throttle cable.

With such an arrangement, especially when starting up also referred to as a warm start after a comparatively short downtime before igniting the burners, when filling steam generator tubes of the still-hot continuous steam generator with cold feed water, considerable temperature differences between those assigned to the first gas flue can occur

Steam generator tubes and a peripheral wall of the horizontal train associated steam generator tubes occur. Such temperature differences can cause inadmissible thermal stresses in particular at a connection point at which a peripheral wall of the first throttle cable is welded to a wall of the horizontal cable. Due to such thermal stresses, especially in the case of frequent start-up processes, the service life of such a continuous steam generator is only limited as a result of high alternating stresses. The thermal voltages occur to a particular extent after the continuous steam generator has only come to a brief standstill, that is to say, for example, after a night standstill, since the continuous steam generator then usually has a higher temperature than the feed water temperature.

The invention is therefore based on the object of specifying a two-pass steam generator which has a particularly long service life even with frequent start-up processes. In addition, a particularly favorable method for starting up such a once-through steam generator is to be specified.

With regard to a once-through steam generator of the type mentioned above, this object is achieved according to the invention in that a bulkhead heating surface is connected directly downstream of the outlet header on the flow medium side. The bulkhead heating surface is to be understood as a number of steam generator tubes connected in parallel for the flow of the flow medium and opening into a common inlet and a common outlet header, the steam generator tubes lying close together in one plane and thus forming a number of plate-like heating surfaces. which are suspended within the throttle cable.

The invention is based on the consideration that for a particularly long service life of the once-through steam generator, the thermal stresses between the peripheral wall of the first throttle cable and the walls of the horizontal throttle cable should be kept particularly low, even with frequent starting operations. For this purpose, the temperature differences between the steam generator tubes, which are filled with cold feed water and assigned to the first gas flue immediately before the burners are ignited, and the walls of the horizontal gas flue, which are still comparatively hot during a warm start, should be kept particularly low.

For this purpose, on the one hand the outlet header of the steam generator tubes assigned to the first gas flue is arranged at a height such that direct contact of the steam generator tubes filled with cold feed water before starting is avoided with the walls of the horizontal gas flue that are still hot during a warm start. On the other hand, for a particularly effective cooling of the steam generator tubes assigned to the horizontal gas flue, the heating surfaces provided for steam generation are dimensioned particularly large during the start-up. For this purpose, the bulkhead heating surface is connected downstream of the steam generator tubes forming the evaporator heating surface as an additional heating surface provided for steam generation.

Advantageous embodiments of the invention are the subject of the dependent claims.

The bulkhead heating surface is expediently in a room area within the first gas flue above that in the first Throttle cable provided combustion chamber. The bulkhead heating surface is thus arranged in a particularly heated area when the continuous steam generator is started up and contributes to a particularly high degree to the steam generation. Thus, even when the continuous steam generator is started up, a large amount of steam is generated, which contributes to a particularly effective cooling of the steam generator pipes which are arranged downstream of the steam generator pipes and are designed as superheater pipes.

For particularly low thermal stresses between the wall heating surfaces of the first gas train and the wall heating surfaces of the horizontal gas train, in an area above the burners arranged in the first gas train and below the lower edge of the gas train, there is advantageously an approximately horizontal dividing line between steam generator pipes filled with water when starting up and steam filled when starting up intended. This dividing line can be designed such that the thermal stresses occurring at this point are kept particularly low. A coincidence of differently cooled heating surfaces in the transition area from the first accelerator cable to the horizontal accelerator cable is thus reliably avoided.

For this purpose, an advantageous embodiment of the evaporator tubes through which the evaporating flow medium flows and which is separated from the superheater tubes through which evaporated flow medium flows, is connected downstream of the bulkhead heating surface on the flow side. In a further advantageous embodiment, a steam-side outlet of the water-steam separating device is connected to an inlet header for a number of further steam generator tubes provided as superheater tubes, these steam generator tubes forming the upper part of the peripheral wall of the first gas flue, and this inlet header in one compared to Lower edge of the horizontal throttle cable is arranged at a lower height. With regard to the method for starting up such a two-pass continuous-flow steam generator, the above-mentioned object is achieved in that after the onset of water ejection from the steam generator tubes forming the evaporator heating surface, the flow medium throughput thereof is temporarily reduced.

When a continuous steam generator is started up, a part of the undevaporated flow medium or water contained in the evaporator tubes is replaced by steam. This process takes place during start-up and leads to a briefly increased flow medium throughput at the outlet of the evaporator tubes, also known as water output. The water output usually has to be removed from the once-through steam generator and therefore causes heat loss for the once-through steam generator.

In a particularly favorable method for starting a once-through steam generator, the water output should therefore be kept particularly low. This is achievable for the continuous steam generator shown above by first filling the steam generator tubes assigned to the peripheral wall of the first gas flue with undamped flow medium up to a height of the outlet collector connected downstream of them before igniting the burners. Excess unevaporated flow medium or water can be passed directly to the water-steam separating device bypassing the bulkhead heating surface via a bypass valve. When the burners are ignited, an initial mass flow of flow medium or feed water is initially supplied to the steam generator tubes designed as evaporator tubes. The flow medium partially evaporates in the steam generator tubes opening into the outlet header, the non-evaporated flow medium reaching the bulkhead heating surface downstream of the outlet header. Since this is also designed as an evaporator heating surface and is therefore filled with undevaporated flow medium cυ cυ to to P> P ¹ cπ O Cπ o Cπ o Cπ

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An embodiment of the invention is explained in more detail with reference to a drawing. In it showed:

1 schematically shows a once-through steam generator in

Double-pass design,

2 shows a section of a peripheral wall of the once-through steam generator according to FIG. 1, and

3 shows an inlet header and an outlet header of the once-through steam generator according to FIG. 1.

Identical parts are provided with the same reference symbols in all figures.

The continuous steam generator 1 according to FIG. 1 comprises a number of burners 2 for a fossil fuel, which are shown schematically in FIG. 1 on the basis of their main axes. The burners 2 are arranged in a combustion chamber 4, which is formed by a lower part of the peripheral wall 6 of a vertically arranged first gas flue 8. The surrounding wall 6 merges into a funnel-shaped base 10 at the lower end of the first throttle cable 8 formed by it.

The continuous steam generator 1 according to FIG. 1 is of the two-pass design. For this purpose, a second gas train 14 is connected downstream of the first gas train 8 for heating gas resulting from the combustion of the fossil fuel via a horizontal gas train 12. The second throttle cable 14 is also arranged vertically.

The surrounding wall 6 of the first throttle cable 8 is constructed from steam generator tubes 16, 17, which are connected to one another in a gas-tight manner on their longitudinal sides, for example welded. In an analogous construction, the surrounding wall 18 of the second throttle cable 14 is also made of steam LO o to ro P>P>

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Φ TJ rt et F- Φ EP Φ yQ vQ Q Φ cn TJ cn P- Q rt Φ rt PJ: P o yQ Φ et

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Φ dd φ d tr vQ cd ri ^¬ d rt P Φ o • F- CΛ dr 3 d ι-i Φ d &

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Φ cn PJ: cn tr P d iQ φ rt Φ P W F- ω rt P- CΛ P 3 Hi N P tr fö Φ tr

Φ d Φ ^• »tr ω tr P- Φ d Φ et P o F- P cn φ cn 3: Φ Φ d SJ F- P PJ PP

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Φ P cn d φ cn d P σ J cn H cn d Ω P rt PJ P> cn cn P> υ P

PP cn ω et yQ α P cn CΛ CΛ PJ et cn Φ o tr Φ F- h- ^y tr φ

Φ P <Ω 3 d cn * "F- 3 φ cn Φ rt ro ä d Φ Cn T, Φ Φ o φ φ Φ P TJ Ct P DJ P d Φ tr PS! Et ZPOP φ Φ tr TJ P Φ PJ F - cn Λ rt P 4 ^ CΛ Hi Pi 3 ti Φ d cn

P J Φ PJ: tr 1 F- P o Hi Ω P d rt TJ Ω J DJ Φ yQ 3 d F- Φ

Pi Φ tr cn cn csi P ö Ω Hi rt Φ tr 1 d et Φ tr Φ to φ 3 φ d P Φ iQ d Ω P rj

PJ d φ cn P d Φ J tr: rt P ö φ Z F- p: tr, fc »P: F- iQ PO: Φ Φ DJ: tr dd cn φ F ¹ Hi 3 Φ Q tr N et DJ et cn Φ cn et φ et d cn ω O Hi Hi P Ω ro P

<Q P> o ι-i Φ d = DJ TJ d d Φ Φ P- 3 P> F- tr d d PJ & Φ 3 tr Hi d = cn tr et Ω

CΛ CTi d PJ Hl F- tr d Hi et d P- d Φ TJ tr PJ rt DJ P- Hi PJ 3 φ Z DJ F d cn F- Ct tr

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PJ d P cn P Φ d φ P σ Cn P d F tr Φ> Q rt φ cn Φ PJ »• σ g d

CΛ iQ cn rt Φ rt Q σ Φ DJ rt PJ: P cn P tr et φ ö cn φ Φ d Φ d d 3 F- 3 et Hi φ Φ o d. F- d 3 Φ Ω o pj: φ Φ φ d φ> cn P cn cn £ σ F- cn Pi Φ

Pi yQ EP cn Φ F ¹ d TJ tr tr tr rr d F- 3 et P d PJ Ω tl σ rt yQ F- DJ rt DJ 3 DJ et d: φ P- α <Hl φ Φ PN d cn h- ^y tr φ PJ <P φ rt cn N cn φ tr P tr DJ d Φ o TJ d Φ h-- <! Cd> P- d Z cn PJ cn 3 Φ O tr dd cn Φ TJ cn P P- Φ d φ rt PP α IO d F- o Φ dd F- P- F ¹ rt TJ P 3 F- et Cd d P d P Hl rt d N cn ω φ PO φ Ti o P et cn Ω P rt Hi et Φ * <<d cn φ to t? Φ iQ Φ d F- et P> tr P PJ rt et tr i Φ Φ PJ Φ PJ PJ 3 TJ Φ tu yQ rt P d P- Ct d Ω dt F- CTi F- PP Φ rt d P rt d P 3 d Φ DJ PO: cn Φ N

Hi £ N Ω Φ d ö tr φ cn N Ω Hi F- P d et Φ N TJ rt csi cn Ct tr ≤ d φ

PJ PJ d tr PP DJ rt rt F- rt- PJ d tr rt <yQ J CΛ Φ Hl CΛ Φ = CΛ PJ Φ DJ d tr cn d 3 d F- N - ^y rt: rt CΛ Φ Φ 3 CΛ TJ d rt TJ dd <! 3 d CD iQ

P cn tr Φ CΛ iQ J d O Hl Ct cn et d tr cn Ω P d TJ Ω φ yQ φ et Φ TJ et et PJ Φ

TJ Φ P ⁾ rt Ω Φ Hi Q d P ¹ F- Φ d Φ cn d "et Hi tr F- Φ F- F- ü Φ d Hi Φ cn P

P d Φ tr ι-i Φ fjj: Φ d iQ P PJ o J 3 Φ o cn P d cn PJ d rt rt cn σ N cn o cn rt do P- P co N Ω φ 3 rt 3 F- P rt Φ P Φ 3 F- Φ d

N rt Φ rt d N 4- ^ d tr F- P PJ cυ et rt TJ rt tr rt Z o et Z TJ α i- ¹ 3 F- tr iQ F>

Φ P d V rt iQ Φ P Φ d 4-. P- h- ~ tr Hi Φ tr PJ tr Φ PJ Hi Φ tr F- cn o Φ tr φ dd cn J cn φ Φ Φ rt d F- φ cn P d cn φ P j-> CΛ d h- ^y 00 s: cn 3 cn φ d yQ DJ CΛ cn yQ 3 NP F- Φ d N F- ω Φ cn P o rt Φ et Φ φ Z rt P- φ Ω P- O φ TJ <d Cd N <Hl N φ d F- Φ N Cd ι- (d φ NP cn PJ P- N s li tr Ω 3 cn Hi Φ Q ^> <to Hi tö φ h- ^y Hi P d P φ P F- O: dd et d P PJ Hl PJ P yQ tr F- PJ Φ U φ TJ J- »Φ P DJ: - ^y F ¹ d Φ CΛ 3 d et yQ Φ

<et d h- ^y cn o φ Φ rt 3 F et Hl J DJ: cn Ct Ω PJ: P- CT) Ct N yQ d rt d DJ Φ φ do CΛ DJ: CΛ tr cn P rt tr PJ = cn PJ Ω rt PJ tr Ω d φ d φ dd Ω d O d TJ et d Ω φ P Ω Φ tr φ 3 tr cn d tr 3 φ "rt d iQ P Φ F- Q tr F φ Φ d tr d Φ tr d Φ N F- TJ P - • cn Φ DJ TJ φ Ct Φ Φ FP d cn yQ uo φ P- P φ CΛ J cn d N Hl rt Φ rt d Hi DJ F- F- Hl o 3 Φ DJ d P

F- cn Φ rt F- F ¹ OP Hi Φ F- P to rt d ro Φ dd: tr to et φ cn 3 φ d Φ et F to P cn rt: d> - • P s: rt Φ CD CΛ Φ cn CTi s: cn tr H F- et Ω TJ rt et φ Z Φ et CT) o rt Φ tr σ DJ: P φ d rt TJ 3 iQ et φ 1 P φ s: Φ F- tr Hl Φ Φ

3 PJ d PJ 3 rt h- ¹ Φ PJ Ω o F d Φ <! Φ φ iQ Φ F- rt d P- cn P DJ Φ d 3 ω M PJ cn cn Φ d P 3 tr tr ^| Q d φ P- P ^J φ 3 ω • F φ 3 P * P • cn TJ dodd CΛ TJ Φ P φ Ct P cn φ 1 Φ F ¹ et 3 • _^ rt 1 φ Hl cn J 1 ^ Q Hi Φ d J-> Φ 1 φ Q CTi Φ F-

1 P 1 1 d 1 • ro d 1 rt 1 3

O cυ ro to P ¹ F ¹ cπ o cπ o cπ O Cπ

3 et F PJ Φ <tr α rt rt iQ Cd ro et iQ Φ tr P P- rt cn CD Hi d et N o σ 3 Hi cn Pi d Φ d:} - • P Φ φ d Φ P Φ φ .fc »Φ pj: F- Φ Φ cn P Φ PJ Φ P Φ d P d φ = Φ PJ d P tr cn NP F- P d Φ P tr P dd F- F- rt F- P CΛ d et d PJ: vQ Ct P tr P- d Q φ N Φ Hi 3 Ω rt Φ P φ d vQ Φ Ω. rt N • Ω φ d Ω φ P d vQ cn <P d - dd: tr Φ P- o F- d σ Φ cn P ^J rt Z d: tr tr cn φ tr P- rt φ cn

3 Φ tr yQ yQ dd tr N Ct PJ d tr F- ö cn PJ vQ S3 Φ Φ Φ rt cn φ PZ φ P tr vQ Φ φ d% et Ct Φ P d 3 Φ Ω <l DJ cn PJ Φ pj: d F- F ¹ Φ et rt φ et et P- Φ PP d Hl F- Φ Φ d et TJ DJ CΛ tr O cn PJ yQ P 3 ro ro d φ d £ s P

F- D> d Z tr P vQ DJ φ d F yQ φ Hi d O Φ 3 3 Φ CD 3 3 ro dd DJ rt d 3 DJ PJ: F- O tr φ cn Φ Hi d P> 3 P * • Φ P- PJ ω v CΛ cn

3 TJ d tr rt tr CΛ P CΛ Sl 3 T) d P Ξ Ct φ d Φ F> CΛ rt% P- d P P- CΛ Φ PJ

Hl cn PNP rt Φ Ω PJ: TJ d MN Φ Φ <P Hi Φ Ω to TJ Hi cn v Φ d Φ dd iQ Φ} - • φ Φ Φ d tr F φ F- Ct P- Φ P- P φ CΛ rt P tr "" P> ü PJ rt φ d Φ d; cn

Φ P PJ Φ P d tr o 3 P 3 dd CΛ CΛ P rt P rt F> d DJ tr od et cn cn d vQ cn tr d F- P rt Φ rt φ PJ o rt vQ rt 3 Φ Φ ro Φ JS ^ d 3 P φ P Φ Φ rt d Φ

Ω Φ Ω cn O F- rt cn rt <et P Φ • F- d rt d TJ Φ F- et PP σ P vQ tr tr F- tr rt tr CT) d tr TJ d Φ Φ F- P PJ Φ Φ Pl d Hl ddddd O Φ

PJ N Φ P d Φ φ PJ P P P r r P rsi d et CD d d P O: iQ φ Φ tu H 3 s: d

Hl Pi Φ d Φ cn 3 F- d <yQ rt O d> Q Φ PJ d Φ d Φ yQ 3 rt ro O: Ω F- Ct

Hi F- • rt J tsi d Φ F ¹ d cn tr Ct φ d cn <! et ddd Φ F- DJ Φ tr tr DJ P φ PJ = d PJ P Φ d Pi d P Φ d cn P φ - NO d Φ Hi rt ddd Φ d Ct N d Ω ö d O: P- CΛ F- d yQ F- rt PJ Φ 3 tr "dd et d N C- dd PJ d

• tr rsi d cn 3 d P DJ: Q <> - • Ω Φ 3 φ CΛ ^| Q d F- z} - • S DJ: et N d CΛ d

Φ ZP ^• Q d Φ φ Ω Φ Φ tr P 3 F ¹ P- tr O 23 P d et F- DJ tr d Z Pi TJ Φ u: ü F- Ω φ d F- tr d F- cn CT, cn Φ 00 PJ: Ω F- DJ cn rt CΛ Φ cn et P- et φ P Ω

PJ to cn tr tr yQ CΛ Ω φ Ω N Ω Φ ~ rt d et F tr Φ tr Ω Φ CΛ P rt Φ cn DJ F- tr

CΛ to Ω F- CΛ F- tr cn tr d P h-> cn DJ PJ 3 Φ tr d Φ d PP Ω 3 cn cn tr et P ¹ 3 Ω Φ ro P- 3 F- cn J et EP d φ et PJ P Φ P et F- tr TJ Φ Φ rt

F- PJ Φ F- φ tr d CT, d fu: et Φ d PJ Hi ω Φ dd σ rt Φ Hi Z dddd Φ Φ et Φ et Ct EP Φ et cυ F- Hi d Ct TJ d Hi DJ vQ z rt dd φ DJ <cn cn rt F- P F- F- d 00 3 yQ Φ Φ PJ rt O tr 3 Φ DJ cn rt H cn ö O et vQ TJ CΛ φ d Φ Q CΛ cn vQ F- PPP Φ d MPH Φ TJ Hi DJ cn Φ α N cn PJ P

F- o cυ

Φ Φ Ω d 3 P rt d z Ω PJ Cd d d d P- Φ d d Hi C- iQ PJ P Φ Φ Φ 3:

Φ cn F- tr cn ^ o 3 d φ tr d φ d J σ d d rt Φ PJ Φ Φ 3? d d P TJ tr rt Ω O s: cn d: EP N P- u3 F- φ Ω P Ct d d tα d rt Φ tr Ω P P 3 PJ vQ Hl Φ

CΛ O tr rt Φ tr φ d rt rt P tr φ Ω P O vQ P d 3 tr N rt Φ d et Φ TJ Φ F

Ω EP Φ rt F- F- P ¹ α vQ Φ F- Ct tr Ω P φ F- tr Φ Φ Ω Φ rt Φ FPP vQ tr Φ F, tr rt rt d <Φ tr Φ P Ά tr Ω Φ tr P - d rt F- DJ dd tr P Φ 3 CΛ ON φ

O d Φ Φ P- d φ 3 Φ z Φ C- Φ tr P tr h- ¹ N rt et Ω P iQ rt TJ Φ tr rt Φ Hi F- P ^| Q vQ P cn PJ: d tr F- φ PJ O F- cn F- tr rt φ σ Φ to 4-> Φ O d Φ rt ω: OJ Φ et CΛ o ^{^} h- "et P- ddd cn Φ Φ P DJ Ji »li PQ d tr F Hi dd PJ DJ F- d P ö dd Φ Φ Pi rt J F- d P 3 Hl cn Φ rt Φ P- φ d PJ d 3 Ω et PJ dd cn P tr Ct PJ φ 3 et d O TJ P rt F- F- P

F- d tr tu: σ Ω Ω TJ tr Φ φ 3 Q rt N PJ: PJ P ^J F- 3 ds! tr Hi φ Φ Φ Φ d OPH

N <Φ Ω PJ tr tr Hi Φ P F- TJ Φ> PJ d 3 Q d F ¹ P α DJ P φ d P cn d vQ d O Φ

Hl φ P- tr 3 vQ Φ P ω CΛ Pi P d tr Pi TJ J φ Φ Ω Φ d Φ P d Φ J tr et

P 3 φ TJ Φ p. P vQ rt Φ Φ cn ω d F- Hl cn 3 P d ^J P et d N tu CD CΛ H d

PJ: et Hi cn Φ tr φ iQ φ P P Ω rt rt iQ Φ N rt φ F- Φ o DJ rt Φ N

Ω J ro φ Ω P Φ cn φ rt N tr P Φ φ P dc cυ et g Φ P> dd PP Cn Φ N d F- tr ä & CTi P tr P- rt P • Φ ü F- F- dd N iQ tr 00 Φ 3 F- vQ F- et F- N F- d Φ

Φ TJ Hi N PJ et N Φ F- d PJ φ rt Φ φ d yQ F ¹ φ Φ PJ N d ^ PP

Hi DJ F- Φ Φ Hi d σ ^y Q α rt F ¹ P yQ F- φ TJ cn d> d Ct φ Φ iQ P 3 ov rt CTi rt ro rt tr cn d rt d F ^J iQ to iQ Φ tr d Φ PN TJ d • ^. σi Φ F rt- yQ Φ pj: rt Φ P Hi P- ω O Hi Φ PJ Hi dd ω oz Hi rt 00 Φ N cn φ φ rt σ Ω iQ P Φ Ω PJ P PJ P P- d F- cn d et Ω tr F- Φ PJ dd ≥: Q d Ct P Φ PJ tr φ PJ o P tr 3 et tr cn Q d 1 iQ Φ tr P cn PF ^ N Φ vQ J φ CΛ DJ P d M Φ et tr d tr N Φ 3 p P rt cn F- P DJ Φ Ω tr iQ d F Φ Ω

1 rt DJ 1 O "TJ DJ J Pi P Φ P t- ¹ d <tr Φ α Hi d tr Φ DJ vQ z 1 tr

P d tr Hl N EP P- 1 Φ d Φ d o α Φ P F- 1 Φ F- cn Φ PJ:

O: cn P 1 d 1 d 1 P iQ PJ 1 rt Φ F »d N 1 1 P 1 Φ P cn 1 1 1 1 1

reached undevaporated flow medium evaporates there, so that the water output of the once-through steam generator 1 when starting and the associated heat loss is particularly low.

Claims

claims

1. continuous steam generator (1) with a first gas train (8), which is followed by a second gas train (14) on the hot gas side via a horizontal gas train (12), a number of steam generator pipes (16) connected in parallel for the flow of a flow medium to one another an evaporator heating surface (22), which is part of a peripheral wall (6) of the first gas flue (8), and the evaporator heating surface (22) forming the steam generator tubes (16) on the output side in a common one, in comparison to one Lower edge (44) of the horizontal gas flue (12) of lower height arranged outlet manifolds (24) open, characterized in that the outlet header (24) is connected downstream of a bulkhead heating surface (26) on the flow medium side.

2. Continuous steam generator (1) according to claim 1, wherein the bulkhead heating surface (26) is arranged in a space (32) within the first gas flue (8) above a combustion chamber (4).

3. continuous steam generator (1) according to claim 1 or 2, in which the bulkhead heating surface (26) on the flow medium side is followed by a water-steam separating device (34).

4. continuous steam generator (1) according to claim 3, wherein a steam-side outlet (36) of the water-steam separating device (34) to an inlet header (38) for a number of other, in the peripheral wall (6) of the first throttle cable (8) guided steam generator tubes (17) is connected, which is arranged at a lower height than the lower edge (44) of the horizontal throttle cable (12).

5. The method for starting a continuous steam generator (1) according to any one of claims 1 to 4, in which after the onset of water discharge from the evaporator heating surface (22) forming the steam generator tubes (16) the flow medium throughput is reduced.

6. The method according to claim 5, wherein the flow medium throughput through the evaporator heating surface (22) forming the steam generator tubes (16) after its lowering is adjusted in proportion to the heat output of the continuous steam generator (1).