US20110265475A1 - Method and apparatus for cold starting a steam turbine - Google Patents
Method and apparatus for cold starting a steam turbine Download PDFInfo
- Publication number
- US20110265475A1 US20110265475A1 US13/099,738 US201113099738A US2011265475A1 US 20110265475 A1 US20110265475 A1 US 20110265475A1 US 201113099738 A US201113099738 A US 201113099738A US 2011265475 A1 US2011265475 A1 US 2011265475A1
- Authority
- US
- United States
- Prior art keywords
- steam turbine
- coil
- turbine component
- component
- steam
- 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
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K13/00—General layout or general methods of operation of complete plants
- F01K13/02—Controlling, e.g. stopping or starting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
- B24B49/10—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation involving electrical means
- B24B49/105—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation involving electrical means using eddy currents
-
- 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
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/08—Cooling; Heating; Heat-insulation
- F01D25/10—Heating, e.g. warming-up before starting
-
- 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
- F05D2260/00—Function
- F05D2260/85—Starting
Definitions
- the disclosure relates to a method and apparatus for cold starting a steam turbine and to a pre-heating step of a starting process.
- valve housing temperature and saturated temperature at turbine start-up can be in excess of 280° C. This temperature difference defines a cold start. Without pre-heat, the application of live steam to the valve during a cold start can lead to rapid condensation heating of an inner surface of the valve housing which can result in high thermal stresses. Such high stress can dramatically reduce the life of the valve. This situation can be overcome by pre-warming the valve to minimise the difference between saturated steam temperature and valve housing temperature during cold start-up.
- Known methods of preheating can involve electrical radiators/blankets or condensate applied to an outer surface of a steam turbine component such as a valve. These methods can have a disadvantage that applying heat only to the surface of the valve can result in a preheating temperature gradient across the entire valve. To avoid excessive stress during the pre-heat that can be created by this gradient, the preheating rate can be limited. Due to this, the heat-up rate can become a time limiting factor in the cold starting of a steam turbine.
- a method for preheating a steam turbine component which includes providing an electro-magnetic coil; locating the coil relative to the steam turbine component so that the coil forms eddy currents in the steam turbine component when AC is applied to the coil; and providing AC to the coil so as to heat the steam turbine component by the eddy currents.
- An apparatus for preheating a steam turbine component, including an electro-magnetic coil for arrangement relative to a steam turbine component so that the coil will form eddy currents in the steam turbine component when AC is applied to the coil; a temperature measurement device for measuring a temperature of the steam turbine component; and a controller for controlling an AC supply to the coil based on temperature of the steam turbine component.
- FIG. 1 is a perspective view of a component with an exemplary heating system
- FIG. 2 is a block diagram of the heating system of FIG. 1 applied to a steam valve of a steam turbine.
- heating of a steam turbine component takes place by eddy currents that act within the component.
- Internal heating for a given energy input, can produce relatively smaller internal temperature gradients. This makes it possible to increase the energy input and remain below specified (e.g. critical) thermal stress levels. As a result, preheating time can be reduced.
- An exemplary advantage is that the coils do not need to make direct contact with the component and so they are not heated to the same extent as the component. This makes it possible to locate the coils on top of thermal insulation protecting the component. This can provide improved personal safety, and can simplify installation.
- a heat-up process is applied to a steam turbine valve.
- the method is useful for valves due to their complicated geometries and relatively thick walls. These factors make valves susceptible to non-uniform temperature distribution. By internally heating the valve, the effect of complicated geometry can be partially reduced and so the component can be more evenly preheated. It is thus possible to achieve a higher heat-up rate.
- the method can be applied to other steam turbine components, such as pipe joints, that can be susceptible to heat stress due to their geometry.
- FIG. 1 shows an exemplary embodiment of a steam turbine component 10 with a heating system.
- the purpose of the heating system is to preheat the component 10 to bring it up to the temperature specified to, for example, start or restart the steam turbine 20 while limiting, to acceptable levels, heat stress in the component 10 .
- the steam turbine component 10 is, in an exemplary embodiment, made of an electric conducting material. This makes the component 10 conducive to eddy current heating.
- the heating system for the heating of the component 10 includes an electro-magnetic coil 18 and an AC supply 12 .
- an exemplary embodiment includes a controller 14 .
- a component temperature measurement device 16 can be included as part of the control system.
- the electro-magnetic coil 18 is arranged to induce an eddy current in the component 10 . In an exemplary embodiment, this can be achieved by the coil 18 being coiled around the outer surface of the component 10 , as shown in FIG. 1 , without making contact with the component.
- An AC supply 12 in an exemplary embodiment shown in FIG. 1 , is in electrical communication with the coil 18 .
- the AC supply 12 in an exemplary embodiment, varies the AC in the coil at a determined current and frequency suitable for heating the component 10 at a predetermined or defined rate and depth.
- the varying of the AC can be performed by a controller 14 .
- the controller 14 includes a temperature measurement device 16 for measuring the temperature of the component 10 . This enables better control of the heating rate and so permits a closer approach to the maximum allowable thermal stress limit.
- An exemplary steam turbine cold start-up process includes providing a steam turbine 20 , and an electro-magnetic coil 18 , as shown in FIG. 2 .
- the coil 18 can be located relative to a steam turbine component 10 , 10 a so as to enable preheating of the component 10 by eddy currents.
- the component 10 may be a valve 10 a, including, as shown in FIG. 2 , a steam valve 10 a arranged to control motive steam into the steam turbine 20 , a part thereof, a piping component 10 , or parts of the casing of the steam turbine 20 (not shown).
- AC is provided to the coil 18 .
- the heating in an exemplary embodiment, is controlled by varying the AC. In a further exemplary embodiment this heating is made in response to a further measured variable, such as a temperature measurement of the component 10 .
Abstract
The disclosure relates to a method and apparatus for cold starting a steam turbine by preheating a steam turbine component using eddy currents. The process includes providing an electrically conducting steam turbine component, an electro-magnetic coil, and a supply of AC to the coil. The coil is located relative to the component so that the coil is capable of forming eddy currents in the component. In this location, an AC current is passed through the coil thus heating the component.
Description
- This application claims priority under 35 U.S.C. §119 to European Patent Application No. 10 161 772.8 filed in Europe on May 3, 2010, the entire content of which is hereby incorporated by reference in its entirety.
- The disclosure relates to a method and apparatus for cold starting a steam turbine and to a pre-heating step of a starting process.
- Preheating of live steam valves in ultra super critical pressure power generation (USC) plants is desirable in order to limit the thermal stress of the valve's housing.
- For a cold start, the difference between valve housing temperature and saturated temperature at turbine start-up can be in excess of 280° C. This temperature difference defines a cold start. Without pre-heat, the application of live steam to the valve during a cold start can lead to rapid condensation heating of an inner surface of the valve housing which can result in high thermal stresses. Such high stress can dramatically reduce the life of the valve. This situation can be overcome by pre-warming the valve to minimise the difference between saturated steam temperature and valve housing temperature during cold start-up.
- Known methods of preheating can involve electrical radiators/blankets or condensate applied to an outer surface of a steam turbine component such as a valve. These methods can have a disadvantage that applying heat only to the surface of the valve can result in a preheating temperature gradient across the entire valve. To avoid excessive stress during the pre-heat that can be created by this gradient, the preheating rate can be limited. Due to this, the heat-up rate can become a time limiting factor in the cold starting of a steam turbine.
- There is therefore a need to provide a method and apparatus for preheating a valve or component that is susceptible to excessive stress during cold start of a steam turbine in as short a time as possible while minimising the detrimental effect of heat stress.
- A method is disclosed for preheating a steam turbine component which includes providing an electro-magnetic coil; locating the coil relative to the steam turbine component so that the coil forms eddy currents in the steam turbine component when AC is applied to the coil; and providing AC to the coil so as to heat the steam turbine component by the eddy currents.
- An apparatus is disclosed for preheating a steam turbine component, including an electro-magnetic coil for arrangement relative to a steam turbine component so that the coil will form eddy currents in the steam turbine component when AC is applied to the coil; a temperature measurement device for measuring a temperature of the steam turbine component; and a controller for controlling an AC supply to the coil based on temperature of the steam turbine component.
- The disclosure is explained in more detail below with the aid of exemplary embodiments in conjunction with the drawings. All elements that are not essential for directly understanding the disclosure have been omitted. Identical elements are provided with identical reference numerals in the various figures. The flow direction of the media is specified by arrows. In the drawings:
-
FIG. 1 is a perspective view of a component with an exemplary heating system; and -
FIG. 2 is a block diagram of the heating system ofFIG. 1 applied to a steam valve of a steam turbine. - According to an exemplary embodiment of the disclosure, heating of a steam turbine component takes place by eddy currents that act within the component. Internal heating, for a given energy input, can produce relatively smaller internal temperature gradients. This makes it possible to increase the energy input and remain below specified (e.g. critical) thermal stress levels. As a result, preheating time can be reduced. An exemplary advantage is that the coils do not need to make direct contact with the component and so they are not heated to the same extent as the component. This makes it possible to locate the coils on top of thermal insulation protecting the component. This can provide improved personal safety, and can simplify installation.
- In an exemplary embodiment according to the disclosure, a heat-up process is applied to a steam turbine valve. The method is useful for valves due to their complicated geometries and relatively thick walls. These factors make valves susceptible to non-uniform temperature distribution. By internally heating the valve, the effect of complicated geometry can be partially reduced and so the component can be more evenly preheated. It is thus possible to achieve a higher heat-up rate. The method can be applied to other steam turbine components, such as pipe joints, that can be susceptible to heat stress due to their geometry.
-
FIG. 1 shows an exemplary embodiment of asteam turbine component 10 with a heating system. The purpose of the heating system is to preheat thecomponent 10 to bring it up to the temperature specified to, for example, start or restart thesteam turbine 20 while limiting, to acceptable levels, heat stress in thecomponent 10. - The
steam turbine component 10 is, in an exemplary embodiment, made of an electric conducting material. This makes thecomponent 10 conducive to eddy current heating. - The heating system for the heating of the
component 10, in an exemplary embodiment, includes an electro-magnetic coil 18 and anAC supply 12. Although eddy current systems can provide highly predictable heating, an exemplary embodiment includes acontroller 14. A componenttemperature measurement device 16 can be included as part of the control system. - The electro-
magnetic coil 18 is arranged to induce an eddy current in thecomponent 10. In an exemplary embodiment, this can be achieved by thecoil 18 being coiled around the outer surface of thecomponent 10, as shown inFIG. 1 , without making contact with the component. - An
AC supply 12, in an exemplary embodiment shown inFIG. 1 , is in electrical communication with thecoil 18. TheAC supply 12, in an exemplary embodiment, varies the AC in the coil at a determined current and frequency suitable for heating thecomponent 10 at a predetermined or defined rate and depth. - In an exemplary embodiment, shown in
FIG. 1 , the varying of the AC can be performed by acontroller 14. In a further exemplary embodiment, thecontroller 14 includes atemperature measurement device 16 for measuring the temperature of thecomponent 10. This enables better control of the heating rate and so permits a closer approach to the maximum allowable thermal stress limit. - An exemplary steam turbine cold start-up process includes providing a
steam turbine 20, and an electro-magnetic coil 18, as shown inFIG. 2 . Thecoil 18 can be located relative to asteam turbine component component 10 by eddy currents. Thecomponent 10 may be avalve 10 a, including, as shown inFIG. 2 , asteam valve 10 a arranged to control motive steam into thesteam turbine 20, a part thereof, apiping component 10, or parts of the casing of the steam turbine 20 (not shown). To realise the heating of thecomponent 10, AC is provided to thecoil 18. - The heating, in an exemplary embodiment, is controlled by varying the AC. In a further exemplary embodiment this heating is made in response to a further measured variable, such as a temperature measurement of the
component 10. - Thus, it will be appreciated by those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the disclosure is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.
-
- 10, 10 a Component, steam valve
- 12 AC supply
- 14 Controller
- 16 Temperature measurement device
- 18 Coil
- 20 Steam turbine
Claims (11)
1. A method for preheating a steam turbine component comprising:
providing an electro-magnetic coil;
locating the coil relative to the steam turbine component so that the coil forms eddy currents in the steam turbine component when AC is applied to the coil;
providing AC to the coil so as to heat the steam turbine component by the eddy currents.
2. The process of claim 1 wherein the steam turbine component is a steam valve.
3. The process of claim 2 wherein the steam valve controls a flow of motive steam into the steam turbine.
4. The process of claim 1 , comprising:
controlling heating of the steam turbine component by varying AC power and frequency applied to the coil.
5. The process of claim 4 , comprising:
measuring temperature of the steam turbine component; and
varying the AC based on the measured temperature.
6. The process of claim 2 , comprising:
controlling heating of the steam turbine component by varying AC power and frequency applied to the coil.
7. The process of claim 3 , comprising:
controlling heating of the steam turbine component by varying AC power and frequency applied to the coil.
8. An apparatus for preheating a steam turbine component, comprising:
an electro-magnetic coil for arrangement relative to a steam turbine component so that the coil will form eddy currents in the steam turbine component when AC is applied to the coil;
a temperature measurement device for measuring a temperature of the steam turbine component; and
a controller for controlling an AC supply to the coil based on temperature of the steam turbine component.
9. The apparatus of claim 8 , wherein the steam turbine component is a steam valve.
10. The apparatus of claim 9 , wherein the steam valve controls a flow of motive steam into the steam turbine.
11. The apparatus of claim 8 , comprising:
insulation covering the steam turbine component.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP10161772 | 2010-05-03 | ||
EP10161772.8 | 2010-05-03 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20110265475A1 true US20110265475A1 (en) | 2011-11-03 |
Family
ID=43332513
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/099,738 Abandoned US20110265475A1 (en) | 2010-05-03 | 2011-05-03 | Method and apparatus for cold starting a steam turbine |
Country Status (4)
Country | Link |
---|---|
US (1) | US20110265475A1 (en) |
JP (1) | JP2011236905A (en) |
CN (1) | CN102235186A (en) |
DE (1) | DE102011018935A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012119839A1 (en) * | 2011-03-04 | 2012-09-13 | Siemens Aktiengesellschaft | Steam turbine, particularly for solar-thermal power stations |
US9404380B2 (en) | 2013-04-30 | 2016-08-02 | General Electric Company | Turbine thermal clearance management system |
EP3460205A1 (en) * | 2017-09-22 | 2019-03-27 | Siemens Aktiengesellschaft | Method for operating a steam turbine |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102014220370A1 (en) * | 2014-10-08 | 2016-04-14 | Siemens Aktiengesellschaft | Keeping a steam turbine shaft warm by induction |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3596034A (en) * | 1969-12-08 | 1971-07-27 | Hooker Chemical Corp | Heat storage |
JPS5412006A (en) * | 1977-06-29 | 1979-01-29 | Toshiba Corp | Preheater for asteam valve body |
US4431890A (en) * | 1980-12-22 | 1984-02-14 | Ramer James L | Induction heated steam flash plug |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2890685B1 (en) * | 2005-09-14 | 2007-12-14 | Snecma | TURBINE HIGH ROTOR ROTOR AUTONOMOUS ROTOR CONTROL IN A TURBOMACHINE |
EP1775431A1 (en) * | 2005-10-12 | 2007-04-18 | Siemens Aktiengesellschaft | Method for warming-up a steam turbine |
JP2009236039A (en) * | 2008-03-27 | 2009-10-15 | Toshiba Corp | Steam valve device and steam turbine plant equipped with the same |
-
2011
- 2011-04-27 DE DE102011018935A patent/DE102011018935A1/en not_active Withdrawn
- 2011-04-27 CN CN2011101134207A patent/CN102235186A/en active Pending
- 2011-05-02 JP JP2011102693A patent/JP2011236905A/en not_active Withdrawn
- 2011-05-03 US US13/099,738 patent/US20110265475A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3596034A (en) * | 1969-12-08 | 1971-07-27 | Hooker Chemical Corp | Heat storage |
JPS5412006A (en) * | 1977-06-29 | 1979-01-29 | Toshiba Corp | Preheater for asteam valve body |
US4431890A (en) * | 1980-12-22 | 1984-02-14 | Ramer James L | Induction heated steam flash plug |
Non-Patent Citations (3)
Title |
---|
English Language Machine translation of FR 2890685 A1 * |
English Language Machine Translation of JP 2009-236039 * |
English translation of JP 54012006 A * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012119839A1 (en) * | 2011-03-04 | 2012-09-13 | Siemens Aktiengesellschaft | Steam turbine, particularly for solar-thermal power stations |
US9404380B2 (en) | 2013-04-30 | 2016-08-02 | General Electric Company | Turbine thermal clearance management system |
EP3460205A1 (en) * | 2017-09-22 | 2019-03-27 | Siemens Aktiengesellschaft | Method for operating a steam turbine |
Also Published As
Publication number | Publication date |
---|---|
JP2011236905A (en) | 2011-11-24 |
DE102011018935A1 (en) | 2011-11-03 |
CN102235186A (en) | 2011-11-09 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: ALSTOM TECHNOLOGY LTD, SWITZERLAND Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KOLLER, MARTIN;REEL/FRAME:026354/0316 Effective date: 20110511 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |