US20090324419A1 - Highly corrosion-resistant movable blade assembly for a steam turbine, in particular a geothermal impulse turbine - Google Patents

Highly corrosion-resistant movable blade assembly for a steam turbine, in particular a geothermal impulse turbine Download PDF

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Publication number
US20090324419A1
US20090324419A1 US12/374,905 US37490509A US2009324419A1 US 20090324419 A1 US20090324419 A1 US 20090324419A1 US 37490509 A US37490509 A US 37490509A US 2009324419 A1 US2009324419 A1 US 2009324419A1
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United States
Prior art keywords
blades
turbine
assembly
metal alloy
weight
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.)
Abandoned
Application number
US12/374,905
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English (en)
Inventor
Luciano Cozza
Mario Zannoni
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.)
Ansaldo Energia SpA
Original Assignee
Ansaldo Energia SpA
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 Ansaldo Energia SpA filed Critical Ansaldo Energia SpA
Assigned to ANSALDO ENERGIA S.P.A. reassignment ANSALDO ENERGIA S.P.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: COZZA, LUCIANO, ZANNONI, MARIO
Publication of US20090324419A1 publication Critical patent/US20090324419A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/14—Form or construction
    • F01D5/141—Shape, i.e. outer, aerodynamic form
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/04—Heavy metals
    • F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
    • F05C2201/0466—Nickel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2220/00—Application
    • F05D2220/30—Application in turbines
    • F05D2220/31—Application in turbines in steam turbines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2300/00—Materials; Properties thereof
    • F05D2300/10—Metals, alloys or intermetallic compounds
    • F05D2300/13—Refractory metals, i.e. Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W
    • F05D2300/131—Molybdenum

Definitions

  • the present invention relates to a highly corrosion-resistant movable blade assembly for a steam turbine, in particular a geothermal impulse turbine, and to a steam turbine, in particular a geothermal impulse turbine, featuring such a movable blade assembly.
  • a steam turbine normally comprises a number of successive stages which, in axial-flow turbines, are arranged coaxially with the turbine (machine) axis, so that the steam discharged from one stage flows directly and more or less axially into the next.
  • the movable part of each stage comprises a number of blades arranged radially about the shaft and fixed to the shaft by fasteners of various types (inverted-pine-shaped or hammer-headed fasteners); and the ends or tops of the blades are connected to one another by shroud rings fixed to the tops of the blades, for example, by riveting (upsetting) pegs formed on the tops of the blades or formed in one piece with the blades themselves.
  • One known application of steam turbines is in geothermal energy generating systems, in which the fluid evolving in the turbine is defined by endogenous natural steam, i.e. steam generated directly in the earth as opposed to steam produced by conventional fossil- or nuclear-fuelled boilers or by heat-recovery boilers as in combination-cycle systems.
  • endogenous natural steam i.e. steam generated directly in the earth as opposed to steam produced by conventional fossil- or nuclear-fuelled boilers or by heat-recovery boilers as in combination-cycle systems.
  • endogenous steam is characterized, not only by much lower than normal thermodynamic conditions (substantially pressure and temperature), but also by uncontrolled chemistry which depends strongly on the site from which the steam is extracted.
  • the steam supplied to the turbine in geothermal systems is normally less than optimum, especially as regards chemical aggression.
  • endogenous steam in fact normally contains various substances in various forms which impart aggressive characteristics to it which are totally absent in industrial steam, and which result in the formation of deposits on the steam turbine blades.
  • the blades and shroud rings are normally made of martensitic stainless steel, such as AISI 403 or similar, which, being a good compromise between mechanical and erosion resistance characteristics, is widely used in steam turbines, even in geothermal systems.
  • a highly corrosion-resistant movable blade assembly for a steam turbine, in particular a geothermal impulse turbine, comprising an array of rotor blades carried by a shaft rotating about an axis; the assembly being characterized in that each blade extends between one end attached to the shaft, and a free end terminating with a top portion with no mechanical connection to the top portions of the adjacent blades; and in that the blades are made of a nickel-based metal alloy preferably also containing chromium, iron, niobium, and molybdenum.
  • the metal alloy contains over roughly 45% by weight of nickel; over roughly 15% by weight of chromium; over roughly 3% by weight of niobium; and over roughly 2% by weight of molybdenum.
  • the metal alloy also advantageously contains smaller quantities of aluminium and titanium, in particular roughly 0.1 to 1% by weight of aluminium, and roughly 0.5 to 1.5% by weight of titanium.
  • FIG. 1 shows a schematic view of a geothermal steam turbine of substantially known configuration
  • FIG. 2 shows a schematic partial longitudinal section of one stage of the FIG. 1 turbine featuring a movable blade assembly in accordance with the invention
  • FIG. 3 shows a partial view of a movable blade assembly in accordance with the invention.
  • Number 1 in FIG. 1 indicates a substantially known steam turbine, which is therefore only shown schematically. More specifically, turbine 1 is an axial impulse turbine of a geothermal power generating system.
  • Turbine 1 substantially comprises a casing 2 having an inlet 3 and an outlet 4 for a stream of endogenous natural steam extracted from the earth.
  • Casing 2 houses a stator 5 integral with casing 2 ; and a rotor 6 connected integrally to a drive shaft 7 extending through casing 2 along a rotation axis A.
  • casing 2 houses a number of successive stages 10 , each defined by an array 11 of fixed stator blades 12 integral with casing 2 and projecting substantially radially from an inner wall 13 of casing 2 , and by an array 14 of movable rotor blades 15 carried by and rotating integrally with shaft 7 .
  • FIG. 2 shows, purely schematically, a stage 10 , in particular an impulse stage 10 , of turbine 1 .
  • Stage 10 comprises a movable blade assembly 20 defined by blades 15 , which are arranged substantially in a ring about shaft 7 and project radially from shaft 7 towards wall 13 of casing 2 .
  • blades 15 have a substantially concave profile, and may be of any known type, e.g. cylindrical with a constant section, tapered and/or twisted.
  • Each blade 15 is fixed in known manner directly to shaft 7 or, as shown in FIG. 2 , to a supporting wheel 21 integral with shaft 7 .
  • Each blade 15 extends between a fastening end 22 , having a connecting portion 23 for connection to shaft 7 , and a free end 24 opposite fastening end 22 and terminating with a top portion 25 in no way connected mechanically to the top portions 25 of the other blades 15 .
  • no mechanical connection in particular no shroud ring, is provided connecting the top portions 25 of rotor blades 15 . Eliminating the shroud ring poses no vibration problems of blades 15 if they are appropriately shaped and sized and exhibit no resonance phenomena with excitation frequencies.
  • assembly 20 and, in particular, blades 15 are made of a nickel-based metal alloy (i.e. in which nickel is the predominant component, and which contains roughly over 45% by weight of nickel) with a high chromium content (roughly over 15% by weight), and also containing iron and significant quantities of niobium (roughly over 3% by weight) and molybdenum (roughly over 2% by weight).
  • the metal alloys used in accordance with the present invention are therefore substantially nickel-chromium alloys containing significant quantities of iron, niobium and molybdenum, together with smaller quantities of aluminium (roughly 0.1 to 1% by weight) and titanium (roughly 0.5 to 1.5% by weight).
  • nickel-based alloys in the Special Metals Corporation INCONEL® group are particularly indicated, and, in terms of corrosion resistance in geothermal applications, have proved far superior to conventional steel, in particular AISI 403 martensitic steel.
  • the INCONEL® name includes a group of nickel-based alloys which can be age hardened, exhibit good creep resistance up to roughly 700° C., and are highly resistant to corrosion in general and to stress corrosion in particular.
  • the movable blade assembly and, specifically, the rotor blades made in accordance with the invention are far more corrosion resistant than blades made of conventional materials;
  • the materials used also have better mechanical characteristics, so that, for a given degree of erosion, resistance is improved and, hence, the working life of the component parts increased;
  • deposits defined by substances in the steam are projected radially outwards onto the stator, and accumulate in particular on stator portions directly facing the top portions of the movable blades, so that subsequent deposits only accumulate up to a certain point, beyond which they are removed mechanically by the top portions of the movable blades which act as scraping tools as they rotate;
  • the movable blade assembly according to the invention may also be used on steam turbines originally designed for conventional solutions, with only minor alterations to the original fixed parts.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
US12/374,905 2006-07-25 2006-07-25 Highly corrosion-resistant movable blade assembly for a steam turbine, in particular a geothermal impulse turbine Abandoned US20090324419A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IT2006/000565 WO2008012842A1 (fr) 2006-07-25 2006-07-25 Ensemble de pales deplaçables hautement résistant à la corrosion pour une turbine a vapeur, en particulier une turbine à impulsion géothermique

Publications (1)

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US20090324419A1 true US20090324419A1 (en) 2009-12-31

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US12/374,905 Abandoned US20090324419A1 (en) 2006-07-25 2006-07-25 Highly corrosion-resistant movable blade assembly for a steam turbine, in particular a geothermal impulse turbine

Country Status (4)

Country Link
US (1) US20090324419A1 (fr)
EP (1) EP2047003B1 (fr)
JP (1) JP2009544895A (fr)
WO (1) WO2008012842A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107559049A (zh) * 2017-09-30 2018-01-09 南京赛达机械制造有限公司 一种高效汽轮机叶片

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6688598B2 (ja) * 2015-11-11 2020-04-28 三菱日立パワーシステムズ株式会社 オーステナイト鋼およびそれを用いたオーステナイト鋼鋳造品

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1800730A (en) * 1929-08-22 1931-04-14 Holzwarth Gas Turbine Co Rotor blade for high-temperature turbines
US3619183A (en) * 1968-03-21 1971-11-09 Int Nickel Co Nickel-base alloys adaptable for use as steam turbine structural components
US20030155047A1 (en) * 1999-03-03 2003-08-21 Daido Tokushuko Kabushiki Kaisha Low thermal expansion Ni-base superalloy
US20050022529A1 (en) * 2003-07-30 2005-02-03 Kabushiki Kaisha Toshiba Steam turbine power plant
WO2005061742A1 (fr) * 2003-11-27 2005-07-07 Siemens Aktiengesellschaft Piece resistant a des temperatures elevees
US20060140775A1 (en) * 2004-12-23 2006-06-29 Nuovo Pignone S.P.A. Vapour turbine

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB283505A (en) * 1927-01-11 1929-04-11 Bbc Brown Boveri & Cie Improvements in means for draining the low-pressure blading of steam turbines
JPH07166803A (ja) * 1993-12-16 1995-06-27 Toshiba Corp タービン動翼および製造方法
JP2001227301A (ja) * 2000-02-15 2001-08-24 Fuji Electric Co Ltd 蒸気タービン
FR2809764B1 (fr) * 2000-05-30 2002-11-29 Framatome Sa Etage de turbine a vapeur axiale
JP2003082476A (ja) * 2001-06-26 2003-03-19 Toshiba Corp 耐食・耐摩耗タービン部材および製造方法
JP2004124751A (ja) * 2002-09-30 2004-04-22 Toshiba Corp 蒸気タービンの湿分分離装置
JP2004169562A (ja) * 2002-11-18 2004-06-17 Toshiba Corp 蒸気タービン

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1800730A (en) * 1929-08-22 1931-04-14 Holzwarth Gas Turbine Co Rotor blade for high-temperature turbines
US3619183A (en) * 1968-03-21 1971-11-09 Int Nickel Co Nickel-base alloys adaptable for use as steam turbine structural components
US20030155047A1 (en) * 1999-03-03 2003-08-21 Daido Tokushuko Kabushiki Kaisha Low thermal expansion Ni-base superalloy
US20050022529A1 (en) * 2003-07-30 2005-02-03 Kabushiki Kaisha Toshiba Steam turbine power plant
US7238005B2 (en) * 2003-07-30 2007-07-03 Kabushiki Kaisha Toshiba Steam turbine power plant
WO2005061742A1 (fr) * 2003-11-27 2005-07-07 Siemens Aktiengesellschaft Piece resistant a des temperatures elevees
US20070071607A1 (en) * 2003-11-27 2007-03-29 Winfried Esser High-temperature-resistant component
US20060140775A1 (en) * 2004-12-23 2006-06-29 Nuovo Pignone S.P.A. Vapour turbine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107559049A (zh) * 2017-09-30 2018-01-09 南京赛达机械制造有限公司 一种高效汽轮机叶片

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Publication number Publication date
EP2047003B1 (fr) 2013-09-04
EP2047003A1 (fr) 2009-04-15
WO2008012842A1 (fr) 2008-01-31
JP2009544895A (ja) 2009-12-17

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Date Code Title Description
AS Assignment

Owner name: ANSALDO ENERGIA S.P.A., ITALY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:COZZA, LUCIANO;ZANNONI, MARIO;REEL/FRAME:022870/0900

Effective date: 20090424

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION