Classifications

• • 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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C6/00—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas- turbine plants for special use
  • F02C6/18—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas- turbine plants for special use using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants
• • 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
  • F22B1/1807—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 using the exhaust gases of combustion engines
  • F22B1/1815—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 using the exhaust gases of combustion engines using the exhaust gases of gas-turbines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F22—STEAM GENERATION
  • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
  • F22B37/00—Component parts or details of steam boilers
  • F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
  • F22B37/10—Water tubes; Accessories therefor
  • F22B37/14—Supply mains, e.g. rising mains, down-comers, in connection with water tubes
  • F22B37/143—Panel shaped heating surfaces built up from tubes

Definitions

• the invention relates to a steam generator, in which a continuous heating surface is arranged in a heating gas duct through which the heating gas can flow in an approximately horizontal direction and which comprises a number of steam generator tubes connected in parallel to the flow through a flow medium, and which is designed in such a way that one in comparison to another Steam generator tube of the same once-through heating surface of a multi-heated steam generator tube has a higher throughput of the flow medium than the other steam generator tube.
• the heat contained in the relaxed working fluid or heating gas from the gas turbine is used to generate steam for the steam turbine.
• the heat transfer takes place in a waste heat steam generator connected downstream of the gas turbine, in which a number of heating surfaces for water preheating, steam generation and steam superheating are usually arranged.
• the heating surfaces are connected to the water-steam cycle of the steam turbine.
• the water-steam cycle usually comprises several, e.g. three, pressure levels, each pressure level having an evaporator heating surface.
• a continuous steam generator In contrast to a natural or forced circulation steam generator, a continuous steam generator is not subject to any pressure limitation, so that live steam pressures well above the critical pressure of water (P Kr ⁇ »221 bar) - where there are only slight differences in density between liquid-like and steam-like medium - are possible are.
• a high live steam pressure favors a high thermal efficiency and thus low CO 2 emissions from a fossil-fired power plant.
• a continuous steam generator has a simple construction in comparison to a circulation steam generator and can therefore be produced with particularly little effort.
• the use of a steam generator designed according to the continuous flow principle as waste heat steam generator of a gas and steam turbine system is therefore particularly favorable in order to achieve a high overall efficiency of the gas and steam turbine system with a simple construction.
• a heat recovery steam generator in a horizontal design offers particular advantages in terms of manufacturing effort, but also with regard to required maintenance work, in which the heating medium or heating gas, that is to say the exhaust gas from the gas turbine, is guided through the steam generator in an approximately horizontal flow direction.
• the heating medium or heating gas that is to say the exhaust gas from the gas turbine
• the steam generator pipes of a heating surface can be subjected to a very different heating depending on their positioning.
• Steam generator tubes can lead to different heating of individual steam generator tubes leading to a merging of steam streams with widely differing steam parameters and thus to undesired losses in efficiency, in particular to a comparatively reduced effectiveness of the heating surface concerned and a reduced steam generation as a result.
• Different heating of neighboring Steam generator tubes can also lead to damage to the steam generator tubes or the collector, particularly in the mouth area of collectors.
• the use of a continuous-flow steam generator designed as a waste heat steam generator for a gas turbine, which is desirable per se, can thus cause considerable problems with regard to a sufficiently stabilized flow guidance.
• a steam generator is known from EP 0944 801 B1, which is suitable for a horizontal design and also has the advantages of a continuous steam generator.
• the known steam generator is designed with regard to its continuous heating surface in such a way that a steam generator tube which is more heated in comparison to a further steam generator tube of the same continuous heating surface has a higher throughput of the flow medium in comparison to the further steam generator tube.
• the continuous heating surface of the known steam generator thus shows in the type of flow characteristic of a natural circulation evaporator heating surface (natural circulation characteristic) when different heating of individual steam generator pipes occurs, a self-stabilizing behavior which, without the need for external influence, leads to an adaptation of the outlet-side temperatures even on differently heated, parallel flow medium switched steam generator pipes leads.
• the known steam generator is comparatively complex in terms of construction, in particular with regard to the water and / or steam side distribution of the flow medium.
• problematic differential expansions can occur between adjacent evaporator tubes, which can lead to inadmissible thermal stresses and thus damage to tubes and collectors.
• the invention is therefore based on the object of specifying a steam generator of the type mentioned above which can be produced with particularly little effort and which can also be used with different thermal stress has a particularly high mechanical stability.
• one or each of the steam generator tubes each comprises an approximately vertically arranged downpipe section through which the flow medium can flow in the downward direction and an approximately vertically arranged riser pipe section downstream of the flow medium side and through which the flow medium can flow in the upward direction.
• the invention is based on the consideration that, in a steam generator that can be produced with particularly low assembly and production expenditure, for a particularly stable and, in particular, insensitive to differences in thermal stress, the design principle of a natural circulation characteristic used in the known steam generator for a continuous heating surface is consistently expanded and should be further improved.
• the continuous heating surface should be designed for an application with a comparatively low mass flow density with a comparatively lower friction pressure loss.
• the steam generator tubes of the once-through heating surface are each divided into at least two segments (of parallel tubes), the first segment comprising all pieces of downpipe and flowing through in the downward direction. Accordingly, the second segment includes all riser pipe sections and is flowed through in the upward direction.
• the contribution of the geodetic pressure ie essentially the weight of the water column, thus acts in the direction of the intended flow and favors this through a positive contribution to the pressure change along the flow path, ie through pressure gain.
• the contribution of geodetic pressure only acts in the second segment or riser section. against the intended direction of flow and thus makes a contribution to pressure loss.
• each steam generator pipe in the heating gas channel is expediently arranged behind the riser pipe section assigned to it in the heating gas direction.
• the steam generator tubes are expediently positioned spatially in the heating gas duct in such a way that the first segment or downpipe section, viewed on the flow medium side, is arranged downstream of the second segment or riser section, on the flue gas side, seen from the flow medium side.
• a particularly simple construction of the once-through heating surface, on the one hand, and a particularly low mechanical load on the once-through heating surface, even with different thermal pressures, on the other hand, can be achieved by, in a further or alternative advantageous embodiment, the downpipe piece of one or each steam generator pipe with the riser pipe piece assigned to it on the flow medium side via an overflow piece connected is.
• F- F- rt N d d d tr F- ro 01 w PJ ⁇ 01.
• the overall flow-promoting geodetic pressure contribution by the upstream down pipe section is particularly large, so that a particularly strong additional supply of flow medium from the assigned down pipe section takes place automatically.
• the automatic additional feeding from the assigned downpipe piece takes place especially for highly heated pipes, so that the desired natural circulation characteristics are particularly enhanced.
• the respective steam generator tube can be designed in such a way that it comprises only one downpipe piece and only one riser pipe piece downstream of this on the flow medium side.
• a particularly high degree of flexibility in adapting the heat absorption capacity of the flow medium flowing through the steam generator tube to the temperature profile of the heating gas flowing through the heating gas channel can, however, be achieved in that a number of the steam generator tubes each comprise a plurality of downpipe and riser pipe sections alternately connected in series on the flow medium side.
• Each of these steam generator tubes viewed in the direction of flow of the flow medium, initially has a first downpipe piece, which, after a suitable deflection, preferably via an overflow piece, is followed by a first riser pipe piece designed to flow through the flow medium in the upward direction. This is followed, preferably also after a suitable deflection via an overflow piece arranged inside the heating gas duct, by a second downpipe piece designed for the throughflow of the flow medium in the downward direction. A second piece of riser pipe is then connected to the second piece of downpipe. Furthermore co co co MM
• F- ⁇ O E ⁇ 01 ⁇ q ⁇ .
• F F> FF rt d 3 F Fi ⁇ ⁇ d tq s: iQ F d 03 3 C ⁇ d 2, F 1 0, ⁇ ! d P- ⁇ tq PJ 03 J iQ rt P- tr d ⁇ q PJ ⁇ & ⁇ 1
• both the downpipe section and the downstream pipe section of each steam generator pipe can each be attached in a hanging construction in the area of the housing cover of the heating gas duct, with a free longitudinal expansion in the lower area being permitted in each case.
• Such longitudinal expansions caused by thermal effects are now compensated for by the overflow piece connecting the respective riser pipe piece to the down pipe piece, so that no stresses occur due to thermal effects.
• Figures 1, 2 and 3 each in a simplified representation in longitudinal section of a steam generator in a horizontal construction.
• the steam generator 1, 1 1 * according to FIGS. 1, 2 and 3 is connected in the manner of a heat recovery steam generator downstream of a gas turbine, not shown.
• the steam generator 1, l ⁇ , 1 each has a peripheral wall 2, which forms a heating gas duct 6 for the exhaust gas from the gas turbine, through which the heating gas direction x can be flowed, in an approximately horizontal direction indicated by the arrows 4.
• a number of heating surfaces designed according to the continuous principle also referred to as continuous heating surfaces 8, 10 and 12 is arranged.
• continuous heating surfaces 8, 10 and 12 In the exemplary embodiments according to FIGS. 1, 2 and 3, only one continuous heating surface 8, 10 and 12 is shown, but a larger number of continuous heating surfaces can also be provided.
• the evaporator system formed from the continuous heating surfaces 8, 10 or 12 can be acted upon with flow medium W, which evaporates once through the respective continuous heating surface 8, 10 or 12 and after exiting the continuous heating surface 8, 10 or 12 dissipated as steam D and superheater heating surfaces are usually supplied for further superheating.
• the evaporator system formed from the respective continuous heating surface 8, 10 or 12 is in each case connected to the water-steam circuit of a steam turbine, not shown in detail.
• a number of further heating surfaces 20, each indicated schematically in FIGS. 1 to 3 are connected in the water-steam circuit of the steam turbine.
• the heating surfaces 20 can be, for example, superheaters, medium pressure evaporators, low pressure evaporators and / or preheaters.
• the continuous heating surface 8 of the steam generator 1 according to FIG. 1, in the manner of a tube bundle, comprises a plurality of steam generator tubes 22 connected in parallel to the flow through the flow medium W.
• a plurality of steam generator tubes 22 are arranged side by side as seen in the heating gas direction x. Only one of the steam generator tubes 22 arranged next to one another in this way is visible.
• the steam generator tubes 22 arranged side by side in this way are each connected upstream of a common distributor 26 and a common outlet header 28 on the flow medium side.
• the distributors 26 are in turn connected on the input side to a main distributor 30, the outlet collectors 28 being connected on the output side to a common main collector 32.
• the continuous heating surface 8 is designed such that it is suitable for feeding the steam generator tubes 22 with a comparatively low mass flow density, the steam generator tubes 22 having a natural circulation characteristic. With this natural circulation characteristic one compares to ⁇ co ho N) F 1 P>
• Hi P- PJ ö 01 EV 01> Hi P- F- ⁇ q Hl 03 ö 03 3 03 t 01 3 Hi C ⁇ 3 ⁇ EV ⁇ q Hi ⁇ ⁇ O ddd et PJ 0 F "d: 01 03 P rt P rt d ⁇ ) rt d ⁇ d tr O ⁇ F 1 F "F-
• each steam generator tube 22 of the continuous heating surface 8 has an almost U-shaped shape, the legs of the U being formed by the downpipe piece 34 and the riser pipe piece 36 and the connecting bend by the transfer piece 38.
• the geodetic pressure contribution of the flow medium W in the area of the downpipe piece 34 - in contrast to the area of the riser pipe piece 36 - produces a flow-promoting and not a flow-inhibiting pressure contribution.
• the water column located in the downpipe section 34 with unevaporated flow medium W “pushes” the throughflow of the respective steam generator tube 22 instead of hindering it.
• the steam generator tube 22 overall has a comparatively low pressure loss.
• each steam generator tube 22 is suspended or fastened to the ceiling of the heating gas duct 6 in the entry area of its downpipe piece 34 and in the exit area of its riser pipe piece 36 in the manner of a hanging construction.
• the spatially lower ends of the respective downpipe piece 34 and the respective riser pipe piece 36, which are connected to one another by their overflow piece 38, are not spatially fixed directly in the heating gas channel 6. Length extensions of these segments of the steam generator tubes can thus be tolerated without risk of damage, the respective overflow piece 38 acting as an expansion bend.
• This arrangement of the steam generator tubes 22 is thus mechanically particularly flexible and insensitive to differential stresses with regard to thermal stresses that occur.
• F- O P d ⁇ ISt F uq F- oi ⁇ ⁇ ⁇ ! ⁇ d tu tr uq • d 01 oi C ⁇ NF tr FN tr 3 F 1 P. ⁇ d Hi ⁇ uq N d uq ⁇ d 03 ⁇ O Hi ⁇ ⁇ o rt ⁇ 01 ⁇ 01 O dd 01 rt ⁇ PL rt d P 0 O dd rt d F PL rt P rt 3 ⁇ ! F- F- F d tu rt P o tr 01
• a plurality of riser pipe pieces 54 are connected, are in turn guided in the exemplary embodiment within the heating gas channel 6 and held in a perforated plate 58. If necessary, however, they can also be laid outside the heating gas channel 6.
• each downpipe section 52 is followed by 2 riser pipe sections 54 connected in parallel on the flow medium side.
• the pipes used have the same dimensions, so that the free flow cross section for the flow medium W in the riser pipe pieces 54 connected in parallel is twice as large as the flow cross section in the down pipe piece 52 upstream of them together.
• such a limitation of the frictional pressure loss in the down pipe pieces 52 can also be achieved by suitable dimensioning, in particular by choosing a comparatively smaller diameter.
• the steam generator 1 * in the exemplary embodiment according to FIG. 3 comprises a continuous heating surface 12, which is also designed for a comparatively low loss of friction pressure and is therefore particularly suitable for ensuring a natural circulation characteristic with a comparatively low mass flow density.
• the flow heating surface 12 of the steam generator l ⁇ is also particularly adapted to the temperature profile of the heating gas flowing through the heating gas channel 6 with regard to its heat absorption capacity.
• each of the steam generator tubes 60 forming the pass-through surface 12 each includes a plurality — in the exemplary embodiment two — of downpipe pieces 62, 64 and riser pipe pieces 66, 68 connected alternately in series on the flow medium side
• the direction of flow of the flow medium W is in each case connected via an overflow section 70 to the first riser section 66 connected downstream of it. This is in turn connected on the output side via an overflow piece 72 to the second downpipe piece 64 connected downstream.
• the second downpipe piece 64 is connected to the second riser piece 66 via an overflow piece 74.
• the Overflow pieces 70, 72, 74 are in turn guided within the heating gas channel 6 and fastened in the floor or ceiling area of the heating gas channel 6 via a perforated plate 76, 78 and 80, respectively.

Applications Claiming Priority (3)

Publications (1)

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• 2001
  • 2001-06-08 DE DE10127830A patent/DE10127830B4/de not_active Expired - Fee Related
• 2002
  • 2002-05-27 RU RU2004100240/06A patent/RU2004100240A/ru not_active Application Discontinuation
  • 2002-05-27 WO PCT/DE2002/001936 patent/WO2002101292A2/de active Application Filing
  • 2002-05-27 SK SK1606-2003A patent/SK287649B6/sk not_active IP Right Cessation
  • 2002-05-27 JP JP2003504017A patent/JP4443216B2/ja not_active Expired - Fee Related
  • 2002-05-27 CA CA002449652A patent/CA2449652C/en not_active Expired - Fee Related
  • 2002-05-27 EP EP02729915A patent/EP1393001A2/de not_active Withdrawn
  • 2002-05-27 CZ CZ20033530A patent/CZ20033530A3/cs unknown
  • 2002-05-27 KR KR1020037016063A patent/KR100718357B1/ko not_active IP Right Cessation
  • 2002-05-27 CN CNB028112822A patent/CN1289853C/zh not_active Expired - Fee Related
  • 2002-05-27 PL PL367197A patent/PL199124B1/pl not_active IP Right Cessation
  • 2002-05-27 US US10/479,994 patent/US6868807B2/en not_active Expired - Fee Related

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