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WO1994010501A1 - Generateur de vapeur - Google Patents

Generateur de vapeur Download PDF

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Publication number
WO1994010501A1
WO1994010501A1 PCT/DE1993/000998 DE9300998W WO9410501A1 WO 1994010501 A1 WO1994010501 A1 WO 1994010501A1 DE 9300998 W DE9300998 W DE 9300998W WO 9410501 A1 WO9410501 A1 WO 9410501A1
Authority
WO
WIPO (PCT)
Prior art keywords
steam generator
straight line
tubes
evaporator
generator according
Prior art date
Application number
PCT/DE1993/000998
Other languages
German (de)
English (en)
Inventor
Rudolf Kral
Eberhard Wittchow
Original Assignee
Siemens Aktiengesellschaft
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO1994010501A1 publication Critical patent/WO1994010501A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B29/00—Steam boilers of forced-flow type
    • F22B29/06—Steam boilers of forced-flow type of once-through type, i.e. built-up from tubes receiving water at one end and delivering superheated steam at the other end of the tubes
    • F22B29/061—Construction of tube walls
    • F22B29/065—Construction of tube walls involving upper vertically disposed water tubes and lower horizontally- or helically disposed water tubes

Definitions

  • the invention relates to a fossil-fired steam generator with a vertical gas flue, the gas-tight tube wall of which is formed in the area near the flame by evaporator tubes arranged obliquely at an angle of inclination a with respect to the horizontal and having internal ribs.
  • fossil-fired steam power plants of the new generation with continuous steam generators are designed for high steam temperatures up to about 600 "C and high live steam pressures from 250 to 300 bar.
  • the steam generator and the steam turbine, as well as the inlet parts of the steam turbine, should be chosen so large that only very low temperature change rates of 1 to 2 K / min are permissible. For this reason, power plants of this type can only be started up slowly, the start-up times being so long and the start-up losses incurred being so high that a large part of the high power plant efficiency is lost again when starting up frequently.
  • a circulating stream is usually superimposed on the evaporator below this partial load of about 35 to 40% of the full load by means of a circulating pump, so that at a correspondingly high flow rate or mass flow density Evaporator tubes are safely cooled.
  • the minimum mass flow density required for this is about 800 kg / m 2 s.
  • mass flow density 2000 to 2300 kg / ms and an acceptable pressure loss of approximately 10 to 12 bar.
  • the minimum mass flow density required in the evaporator tubes must also be approximately 800 kg / m 2 s - corresponding to approximately 4000 kg / m 2 s at full load.
  • the resulting pressure loss for the evaporator alone from 35 to 45 bar at full load is extremely uneconomical due to a substantial reduction in efficiency due to the high power requirement of a feed water pump and the large wall thicknesses of system parts carrying feed water.
  • the invention is therefore based on the object of specifying a steam generator with which high steam temperatures can be achieved even with a minimum load of the steam generator below 30% of the full load. This should ensure safe cooling of the evaporator tubes at low load as well as an economical loss of friction pressure of the evaporator at full load (100% load).
  • the pitch angle ⁇ of the obliquely rising evaporator tubes is a function of the live steam quantity P generated at full load per unit time, the pairs of values P; a are in a range that is limited by a value of 500 t / h; 16 "and 3000 t / h; 42 ° assigned first straight line, and the upper limit is limited by the value pairs 500 t / h; 25" and 2500 t / h; 70 "assigned second straight line.
  • the invention is based on the consideration that with an inclined position of the evaporator tubes and the use of internally finned tubes with a to the steam generator output, i.e. the amount of live steam generated per unit of time, adjusted pitch angle ⁇ , the large number of influencing factors to be taken into account when designing such a steam generator are reduced to only a few.
  • These influencing variables are e.g. the mass flow density in the evaporator tubes, the heat flow density as a measure of the heating, the tube inner diameter, the steam generator output, the minimum partial load and the width of the webs provided between the tubes.
  • the pitch angle ⁇ is expediently greater than 20 °.
  • the pitch angle is advantageously less than 70 °, preferably less than 65 °.
  • the pitch angle ⁇ is adapted in an advantageous embodiment to the selected outer diameter d of the evaporator tubes.
  • the preferred selected standardized outer diameters d of 38.1 mm or 35.0 mm or 31.8 mm are the value pairs Pn: 'a' n in the subclaims 4, 5 and 6 ang 3eg3
  • the obliquely rising evaporator tubes merge into a vertical arrangement in a region in which the heat flow density has exceeded its maximum value.
  • the tube wall is therefore formed in this area remote from the flame, in which the heat flow density decreases, by tubes arranged vertically and parallel to one another.
  • the number of vertically extending tubes is greater than that of the evaporator tubes, which run at an incline.
  • Pipes with a smooth inner surface can also be used in the area remote from the flame.
  • a pressure compensation collector should be arranged at the transition point from the oblique to the vertical pipe.
  • the steam generator according to the invention can also be operated in continuous operation at a low partial load below 30% of the full load, an increase in the evaporator throughput by means of a circulation pump no longer being necessary.
  • a circulating pump with associated pipelines which is nevertheless expediently assigned to the evaporator tubes in terms of flow, is therefore only functional during start-up operation. This results in a minimum throughput through the evaporator and possibly through one of these upstream economizer secured. So that permissible temperature changes during start-up can be as large as possible even with a complicated housing of the circulating pump, the circulating pump and the associated pipes are dimensioned in terms of strength only for a pressure of at most 150 bar. As a result, the wall thicknesses of these plant parts can be kept particularly small.
  • a steam generator output i.e. the fresh steam quantity P generated at full load per unit time P of the steam generator can also be operated at a minimum load below 30% of the full load in the pass and thus at high steam temperatures. This ensures reliable cooling of the obliquely arranged evaporator tubes at minimum load as well as a low loss of frictional pressure of the evaporator at full load.
  • FIG. 1 shows a simplified representation of a steam generator with a vertical throttle cable that is partially touched at an angle
  • FIG 3 greatly simplified a starting system for a steam generator according to Figure 1 with a circulation pump.
  • the vertical throttle cable of the steam generator 2 according to FIG. 1 with a rectangular cross section is formed by a tube wall 4 which merges into a funnel-shaped bottom 6 at the lower end of the gas cable.
  • the bottom 6 comprises a discharge opening 8 for ashes, not shown.
  • a number of burners (not shown) for a fossil fuel are attached in the lower wall 4 near the flame or near the burner for a fossil fuel in the surrounding wall 4 formed from pipes 10.
  • the tubes 10 are arranged in a spiral shape in this area C and form an evaporator heating surface 12.
  • a flame D or burner-remote area D of the gas cable Above area C of the throttle cable is a flame D or burner-remote area D of the gas cable.
  • area D of the gas flue in which convection heating surfaces 14, 16 and 18 are also arranged, the pipes 10 'run vertically.
  • area D of the gas flue there is a smoke outlet channel 20, via which the flue gas RG generated by burning a fossil fuel leaves the vertical gas flue.
  • the area near the flame C is characterized by a high heat flow density, which decreases towards the top in the area D remote from the flame. Therefore, the transition from the spiral arrangement of the evaporator tubes 10 to the vertical tube arrangement expediently lies in a region 22 in which the heat flow density has exceeded its maximum value.
  • the number of vertically extending tubes 10 ′ is greater than that of the obliquely extending evaporator tubes 10.
  • the obliquely extending evaporator tubes 10 advantageously have ribs forming a multi-start thread on their inside.
  • the evaporator tubes 10 form the gas-tight tube wall 4 in the area near the flame C in a so-called tube-web-tube construction.
  • the evaporator tubes 10 are arranged at an inclination angle a with respect to the horizontal H.
  • the pitch angle a is defined as the angle function sin a from the quotient G / L.
  • G is the vertical distance between the transition from the funnel-shaped bottom 6 to the vertical throttle cable and the upper end of the helical winding in the transition region 22.
  • L is the length of an evaporator tube 10 rising with a constant inclination over the vertical distance or the height G.
  • the pitch angle ⁇ of the obliquely arranged evaporator tubes 10 is adapted to the steam generator power P.
  • the dependence of the pitch angle a on the steam generator power P, i.e. the amount of live steam generated at full load per unit time is shown in FIG.
  • FIG. 2 a Pa diagram, in which the steam generator power P is plotted on the abscissa and the gradient angle a on the ordinate, shows an area Z which is delimited by two straight lines E and F upwards and downwards, in which the value pairs P; a lie.
  • the straight line E runs through the points or pairs of values: (500 t / H; 25 °) and (2500 t / h; 70 °).
  • the straight line F runs through the points or pairs of values: (500 t / h; 16 °) and (3000 t / h; 42 °).
  • the straight line A corresponds to a standardized outer diameter d- of 38.1 mm.
  • the gradient angles a corresponding to the straight lines A, B and C are mean values.
  • a particularly favorable gradient angle a which takes into account all requirements and influencing variables, can deviate from the mean value if, for example the web width between adjacent evaporator tubes 10, the wall thickness of the tubes 10, 10 'and the maximum local heat flow density must be adapted directly to the respective application.
  • lines A, B or C a deviation of the pitch angle a by 25%, preferably 20%, is permissible.
  • the slope angle ⁇ can be linearly extrapolated for values of the steam generator output P above 3000 t / h or below 900 t / h.
  • Tube outer diameters d other than the outer diameters d,, d 2 and d, can also be linearly interpolated or extrapolated between or outside the straight lines A, B and C, respectively.
  • FIG. 3 shows schematically and in detail the water-steam circuit 30 of a (not shown) steam turbine of a steam power plant.
  • a 2 water-steam drum 36 is connected, which is connected via a water reservoir 38 and a circulation pump 40 to the outlet of a steam-covered preheater 42 and to the inlet of the economizer 32. Protection against an impermissible excess pressure is carried out by means of a
  • Safety valve 44 The circulation pump 40 and the water reservoir 38 as well as associated pipelines 46 form a start-up system 48 of the steam generator 2.
  • the start-up system 48 only functions when the steam generator 2 starts up.
  • the preheated feed water conveyed by means of a feed water pump 50 and flowing through the economizer 32 and the evaporator 12 and the superheater 34 is superimposed behind the preheater 42 by a circulating flow conveyed via the circulating pump 40.
  • a minimum throughput through the evaporator 12 is ensured by the circulation pump 40 associated with the flow to the evaporator 12 when the steam generator 2 starts up.
  • the circulating pump 40 and the associated pipelines 46 are only designed for a pressure of 150 bar and therefore only have small wall thicknesses.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)

Abstract

L'invention concerne un générateur de vapeur (2) alimenté en combustible fossile qui comprend un carneau vertical dont la paroi tubulaire (4) étanche aux gaz dans la zone proche des flammes (C) est constituée par des tuyaux d'évaporation (10) placés en diagonale par rapport à l'horizontale (H) à un angle d'inclinaison a et comportant des nervures intérieures. L'invention prévoit que l'angle d'inclinaison a soit une fonction a(P) du volume de vapeur fraîche produit par unité de temps lorsque le générateur fonctionne à pleine charge, c'est-à-dire de la puissance P du générateur de vapeur. Les valeurs couplées P, a se situent dans une fourchette (Z) délimitée vers le bas par une première ligne droite (F) associée à 42° aux valeurs couplées 500 t/h; 16° et 3000 t/h; et délimitée vers le haut par une seconde ligne droite (E) associée à 70° aux valeurs couplées 500 t/h; 25° et 2500 t/h. Ce procédé permet d'atteindre des températures élevées de la vapeur, y compris lorsque le générateur de vapeur (2) fonctionne en charge minimale, en dessous de 30 % de la charge maximale, tout en garantissant un refroidissement sûr des tuyaux d'évaporation, en charge réduite, ainsi qu'une perte économique de pression, due au frottement, de l'évaporateur.
PCT/DE1993/000998 1992-11-02 1993-10-20 Generateur de vapeur WO1994010501A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP4236835.9 1992-11-02
DE19924236835 DE4236835A1 (de) 1992-11-02 1992-11-02 Dampferzeuger

Publications (1)

Publication Number Publication Date
WO1994010501A1 true WO1994010501A1 (fr) 1994-05-11

Family

ID=6471822

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1993/000998 WO1994010501A1 (fr) 1992-11-02 1993-10-20 Generateur de vapeur

Country Status (3)

Country Link
CN (1) CN1086592A (fr)
DE (1) DE4236835A1 (fr)
WO (1) WO1994010501A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2175095C2 (ru) * 1996-01-25 2001-10-20 Сименс Акциенгезелльшафт Прямоточный парогенератор и способ расчета прямоточного парогенератора
RU2181179C2 (ru) * 1996-11-06 2002-04-10 Сименс Акциенгезелльшафт Способ эксплуатации проточного парогенератора и проточный парогенератор для осуществления способа
US9194577B2 (en) 2011-03-30 2015-11-24 Siemens Aktiengesellschaft Method for operating a once-through steam generator and steam generator designed for carrying out the method

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08170803A (ja) * 1994-12-16 1996-07-02 Mitsubishi Heavy Ind Ltd 蒸気発生装置
DE19600004C2 (de) * 1996-01-02 1998-11-19 Siemens Ag Durchlaufdampferzeuger mit spiralförmig angeordneten Verdampferrohren
CN102589000B (zh) * 2012-03-07 2014-04-09 上海锅炉厂有限公司 包含用于变截面炉膛中的水冷系统的锅炉

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2214697A1 (de) * 1972-03-25 1973-09-27 Sulzer Ag Brennkammerberohrung
GB2007340A (en) * 1977-11-07 1979-05-16 Foster Wheeler Energy Corp Vapour generating system utilizing intergral separators and angulary arranged furnace boundary wall fluid flow tubeshaving rifled bores
EP0349834A1 (fr) * 1988-07-04 1990-01-10 Siemens Aktiengesellschaft Chaudière à vapeur à passage unique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2214697A1 (de) * 1972-03-25 1973-09-27 Sulzer Ag Brennkammerberohrung
GB2007340A (en) * 1977-11-07 1979-05-16 Foster Wheeler Energy Corp Vapour generating system utilizing intergral separators and angulary arranged furnace boundary wall fluid flow tubeshaving rifled bores
EP0349834A1 (fr) * 1988-07-04 1990-01-10 Siemens Aktiengesellschaft Chaudière à vapeur à passage unique

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DOLEZAL: "Dampferzeugung", 1985, SPRINGER, DE, BERLIN *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2175095C2 (ru) * 1996-01-25 2001-10-20 Сименс Акциенгезелльшафт Прямоточный парогенератор и способ расчета прямоточного парогенератора
RU2181179C2 (ru) * 1996-11-06 2002-04-10 Сименс Акциенгезелльшафт Способ эксплуатации проточного парогенератора и проточный парогенератор для осуществления способа
US9194577B2 (en) 2011-03-30 2015-11-24 Siemens Aktiengesellschaft Method for operating a once-through steam generator and steam generator designed for carrying out the method

Also Published As

Publication number Publication date
DE4236835A1 (de) 1994-05-05
CN1086592A (zh) 1994-05-11

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