US3271961A - Start-up system for forced flow vapor generator - Google Patents

Start-up system for forced flow vapor generator Download PDF

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Publication number
US3271961A
US3271961A US405685A US40568564A US3271961A US 3271961 A US3271961 A US 3271961A US 405685 A US405685 A US 405685A US 40568564 A US40568564 A US 40568564A US 3271961 A US3271961 A US 3271961A
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United States
Prior art keywords
turbine
valve
fluid
zone
vapor
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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.)
Expired - Lifetime
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US405685A
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English (en)
Inventor
Wiener Murray
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Babcock and Wilcox Co
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Babcock and Wilcox Co
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 Babcock and Wilcox Co filed Critical Babcock and Wilcox Co
Priority to US405685A priority Critical patent/US3271961A/en
Priority to FR35540A priority patent/FR1460841A/fr
Priority to DK539465AA priority patent/DK114780B/da
Priority to GB44700/65A priority patent/GB1102168A/en
Priority to SE13649/65A priority patent/SE316783B/xx
Priority to NL6513736A priority patent/NL6513736A/xx
Priority to BE671323A priority patent/BE671323A/xx
Application granted granted Critical
Publication of US3271961A publication Critical patent/US3271961A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • F01K3/00—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein
    • F01K3/18—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters
    • F01K3/20—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters with heating by combustion gases of main boiler
    • F01K3/22—Controlling, e.g. starting, stopping
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B35/00—Control systems for steam boilers
    • F22B35/06—Control systems for steam boilers for steam boilers of forced-flow type
    • F22B35/14—Control systems for steam boilers for steam boilers of forced-flow type during the starting-up periods, i.e. during the periods between the lighting of the furnaces and the attainment of the normal operating temperature of the steam boilers

Definitions

  • This invention relates in general to a power plant system having a turbine arranged to be supplied with vapor from a forced circulation once-through vapor generator and more particularly to apparatus for and a method of starting up such a system.
  • the general object of the present invention is the provision of a starting system of the character described so constructed and arranged as to simplify starting procedme; to provide low cost, rapid, controlled start-ups; to provide adequate protection of the turbine and vapor superheating section of the vapor generator to the end that thermal stresses on this equipment are within acceptable limits at all times; to provide maximum heat recovery during starting up and low load operation; and to permit matching of the vapor temperature to turbine metal temperature on hot restarts and a minimum differential of vapor temperature and turbine metal temperature on cold starts.
  • the invention is directed to improvements in the construction and operation of a start-up system of the type described in US. Patent No. 2,989,038 in which the discharge from the vapor generating section of a once-through boiler is passed into a flash tank, water from the flash tank is conducted to the inlet end of the vapor generating section of the boiler, vapor from the flash tank is passed through the vapor superheating section of the boiler and then condensed for return to the vapor generating section, and provisions are made for bypassing the flash tank when the working medium is properly conditioned for rolling and loading the turbine.
  • a disadvantage of this system, as well as other prior startup systems resides in its inability, especially during col-d start-ups, to provide low temperature steam to the turbine for rolling and loading. As a result, the turbine metal is subjected to excessive rates of temperature change. This drawback is eliminated in accordance with the present invention by special provisions for tempering vapor supplied to the turbine for rolling and loading.
  • FIG. 1 is a schematic diagram of a power plant system embodying the invention.
  • FIG. 2 is a schematic diagram of a modified plant according to the invention.
  • feedwater is supplied by a boiler feed pump through a conduit 11 to a high-pressure heater 12, then passes through a conduit 13 to the circuitry of a vapor generator 14 of the once-through forced flow type having a series fluid flow 3 ,2 71,96 1 Patented Sept. 13, 1966 path including an economizer 16, vapor generating section 17, and superheater 18.
  • Superheater 18 is connected for series flow of fluid from the vapor generating section by a conduit 19 and for series flow fluid to a highpressure turbine 22 by a conduit 23 containing a stop valve 24 and a control valve 26.
  • Valve 24 is by-passed by a conduit 20 containing a stop valve 25.
  • Valves 27A and 28A represent the customary regulating means for the fuel and air respectively.
  • the working medium passes successively through the economizer 16, vapor generating section 17 and superheater 18.
  • the superheated vapor outflow of superheater 18 passes through conduit 23 to the high-pressure stage of vapor turbine 22 for expansion therein, with the vapor then exhausting through a conduit 30 to a main condenser 31, where it is condensed at a low pressure for return to the feedwater system.
  • From the condenser the condensate passes by way of a conduit 32 to a pump 33 from which it discharges through a conduit 34 and low-pressure heater 36 to a direct contact type deaerating heater 37 which serves to boil the condensate to eliminate any entrained oxygen.
  • Condensate from the deaerator passes through a conduit 38 to the suction side of feed pump 10 for return to the vapor generator.
  • a special by-pass system is provided around the superheater and around the turbine.
  • This system is constructed and arranged to obtain highest operational flexibility, to minimize heat losses, and to provide full thermal protection of superheater surface and the turbine; and is used for cold and hot start-ups, for low load operation and for shutdown or emergency trip of the vapor generator.
  • the superheater by-pass comprises a conduit 39 containing a pressure breakdown valve 41 and having one end connected and opening to conduit 19 and its opposite end connected and opening to a flash tank 42, which serves as a receiving vessel for the by-pass fluid and separates steam and water.
  • a conduit 55 containing a control valve 50 and a stop and check valve 60 and having its inlet end connected to flash tank 42 and its discharge end connected to conduit 23 at a point intermediate stop valve 24 and control valve 26. This particular feature will be hereinafter enlarged upon.
  • the turbine by-pass comprises a conduit 43 containing a pressure-reducing valve 44, spray attemperator 46 and attemperator control valve 46A, with conduit 43 having one end connected and opening to conduit 23 at a position intermediate superheater 18 and turbine stop valve 24 and its opposite end connected and opening to condenser 31.
  • Spray attemperator 46 is provided to reduce steam temperature to conditions acceptable to the condenser.
  • Drainage from the flash tank is provided by a conduit 49 containing a deaerator water pegging valve 51 and extending between flash tank 42 and deareator 37; by a branch conduit 52 containing a valve 53 and having one end connected to conduit 49 at a point upstream of valve 51 and its opposite end connected to condenser 31; and by a branch conduit 65 containing a valve 70 and having one end connected to conduit 52 at a point upstream of valve 53 and its opposite end connected to the shell side of heater 12.
  • a conduit 54 controlled by a valve 56, extends between flash tank 42 and the shell side of heater 12; a conduit 57, having a valve 58, has one end connected to conduit 54 at a position upstream of valve 56 and its opposite end connected to deaerato-r 37; and a conduit 59, controlled by a valve 61 leads from the flash tank to the turbine seals.
  • a steam line 62 containing a valve 63 and leading from flash tank 42 to conduit 43 at a position intermediate valve 44 and spray attemperator 46, acts as a flash tank over pressure control by allowing any excess steam to flow to condenser 31.
  • valve 51 is set to maintain flash tank water level below normal. Firing is then commenced and gas temperature entering superheater 18 is held to approximately 1,000" F. As the enthalpy of the fluid entering the flash tank increases, more residual heat is introduced to the deaerator, causing deaerator and flash tank pressure to rise. When deaerator pressure reaches about 20 p.s.i.a., valve 51 starts to close and the flash tank level control valve 70' opens to allow flash tank drains to flow to the shell side of heater 12 to minimize heat loss, with the drains then passing through a conduit 71 to condenser 31. Conduit 71 is controlled by a valve 72.
  • valve 51 controls deaerator pressure and the flash tank level control valve 70 now controls flash tank water level. If the flash tank water level exceeds the normal water level, valve 53 opens to divert the excess water to the condenser. Valve 70 is also controlled to close on high water level in heater 12.
  • valve 51 is closed, since it has a set point of 20 p.s.i.a. deaerator pressure, and valve 70 is open so that more of the flash tank water is diverted to the shell side of heater 12 and thence passes to condenser 31 by way of conduit 71.
  • feedwater temperature is increased and heat is recovered by the use of flash tank steam to deaerator 37 and flash tank drain water in the high-pressure heater 12.
  • the high-pressure feedwater heater steam control valve 56 opens so that excess steam is diverted to the shell side of heater 12.
  • heater 12 pressure will rise, thus increasing feedwater temperature further and recovering more heat.
  • valve 44 is opened so that fluid is directed from the vapor generating section 17 through conduit 19 to and through superheater 18, and then through conduits 23 and 43 to condenser 31, thereby warming up such steam lines and the superheater.
  • Valve 44 is throttled to maintain flow in the superheater and conduit 23 as required for warm up.
  • steam flow is diverted into the turbine by Way of valve 25 and valve 26.
  • flash tank separated steam is directed through conduit 55 for mixing with outflow of superheater 18 when the turbine is ready to be rolled.
  • Combination stop and check valve 60 pre vents flow from the superheater back to the flash tank.
  • the temperature of the separated steam leaving the flash tank is the saturation temperature corresponding to the pressure in the flash tank.
  • valve 25 is controlled to throttle the pressure of the steam down to a level suflicient to roll the turbine, this pressure being about 50 p.s.i.a.
  • valve 24 is closed and valve 50 is controlled so that for each degree of opening of valve 25 there is a set opening of valve 50.
  • the turbine receives a mixture of superheated steam passing through conduit 23 and valve 25 and saturated steam passing through conduit 55 and valve 50.
  • the proportions of superheated and saturated steam in the mixture passing to the turbine may be varied over a wide range by suitable adjustment of valves 50 and 25 to the extent that the turbine may be supplied with steam close to the saturation temperature corresponding to its pressure or steam superheated up to a temperature corresponding to the temperature of the steam discharging through valve 25.
  • the turbine is synchronized and loaded to 5 to 10 percent load by closing down turbine by-pass valve 44. Load may then be increased to about 20 percent of full load by increasing firing rate. At this time, flow to the flash tank will only constitute the difference between startup flow and that passing directly to the superheater and turbine via the valve 25.
  • valve 25 At a predetermined point in the loading of the turbine, control of the turbine is transferred from valve 25 to valve 26. This is done by opening valve 25 while closing valve 26, producing a pressure increase between these valves. This pressure increase will tend to reduce the flow of flash tank steam through valve 50.
  • valve 25 When valve 25 is sufficiently open and valve 26 sufliciently closed so that the pressure upstream of valve 26 is higher than the flash tank pressure, valve 60 will close on check action.
  • valve 24 can be opened wide and valve 25 closed, followed by the closing of valve 41.
  • Normal turbine extraction flows will replace flash tank steam and drain flows for deaeration and feedwater heating.
  • any steam separated in the flash tank in excess of what is required for turbine sealing, deaeration, feedwater heating and turbine operation is discharged through the flash tank over pressure control valve 63 to the condenser.
  • pressure control valve 63 to the condenser.
  • the turbine by-pass conduit 43A has its inlet end connected to conduit 23 at a position intermediate superheater 18 and valve 24 and its outlet end connected to superheater by-pass conduit 39 at a point downstream of valve 41.
  • conduit 39 is provided with a spray attemperator 66 and attemperator control valve 66A at a location downstream of the point of intersection of conduits 39 and 43A.
  • valve 44 is opened so that fluid is directed from the vapor generating section 17 through conduit 19 to and through superheater 18 for warming up such steam lines and the superheater, and then through conduit 43A to conduit 39 for flow to flash tank 42 along with the fluid passing directly from the vapor generating section 17 to conduit 39.
  • Valve 44 is throttled to maintain flow in the superheater and conduit 23 as required for warm-up and to match the pressure on the downstream side of valve 41.
  • a forced flow vapor generator having a through-flow circuit including a fluid heating section and a superheater section connected for series flow of fluid from the fluid heating section and to the turbine, and a pump supplying vaporizable fluid to the fluid heating section
  • means for starting-up the vapor generator and turbine comprising a cut-ofi valve arranged to control fluid flow between the superheating section and the turbine, a flash tank, means for passing a portion of the fluid heating section outflow to the flash tank while passing the remainder of the fluid heating section outflow to the superheater section
  • said last named means including a conduit connecting the fluid heating section to the flash tank and arranged to convey a portion of the discharge from the fluid heating section to the flash tank when said cut-off valve is closed, and a pressure reducing valve in said conduit arranged to cause fluid discharge from the fluid heating section to flash into vapor, means for passing separated liquid from the flash tank to the fluid heating section, means for passing superheater outflow to the fluid heating section, and means
  • a forced flow vapor generator having a through-flow circuit including a fluid heating section and a superheater section connected for series flow of fluid from the fluid heating section and to the turbine, and a pump supplying vaporizable fluid to the fluid heating section
  • means for startingup the vapor generator and turbine comprising a cut-01f valve arranged to control fluid flow between the superheating section and the turbine, a flash tank, means for passing a portion of the fluid heating section outflow to the flash tank while passing the remainder of the fluid heating section outflow to the superheater section
  • said last named means including a conduit connecting the fluid heating section to the flash tank and arranged to convey a portion of the discharge from the fluid heating section to the flash tank when said cut-01f valve is closed, and a pressure reducing valve in said conduit arranged to cause fluid discharge from the fluid heating section to flash into vapor, means for passing separated liquid from the flash tank to the fluid heating section, means for passing super-heater outflow to said conduit at a position downstream of

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)
  • Control Of Turbines (AREA)
US405685A 1964-10-22 1964-10-22 Start-up system for forced flow vapor generator Expired - Lifetime US3271961A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US405685A US3271961A (en) 1964-10-22 1964-10-22 Start-up system for forced flow vapor generator
FR35540A FR1460841A (fr) 1964-10-22 1965-10-20 Dispositif de démarrage pour générateur de vapeur à circulation forcée
DK539465AA DK114780B (da) 1964-10-22 1965-10-21 Fremgangsmåde ved start af en tvangsgennemstrømmet kedel, som føder en turbine, og anlæg til udøvelse af fremgangsmåden.
GB44700/65A GB1102168A (en) 1964-10-22 1965-10-21 Improvements in or relating to forced-flow vapour generators
SE13649/65A SE316783B (da) 1964-10-22 1965-10-21
NL6513736A NL6513736A (da) 1964-10-22 1965-10-22
BE671323A BE671323A (da) 1964-10-22 1965-10-22

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US405685A US3271961A (en) 1964-10-22 1964-10-22 Start-up system for forced flow vapor generator

Publications (1)

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US3271961A true US3271961A (en) 1966-09-13

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US405685A Expired - Lifetime US3271961A (en) 1964-10-22 1964-10-22 Start-up system for forced flow vapor generator

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US (1) US3271961A (da)
BE (1) BE671323A (da)
DK (1) DK114780B (da)
GB (1) GB1102168A (da)
NL (1) NL6513736A (da)
SE (1) SE316783B (da)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4311013A (en) * 1979-02-27 1982-01-19 Hitachi, Ltd. Method of controlling condensation system of steam plant
US4665706A (en) * 1981-05-12 1987-05-19 The Babcock & Wilcox Company Control system for variable pressure once-through boilers
US5390631A (en) * 1994-05-25 1995-02-21 The Babcock & Wilcox Company Use of single-lead and multi-lead ribbed tubing for sliding pressure once-through boilers
US20100107636A1 (en) * 2008-10-30 2010-05-06 General Electric Company Provision for rapid warming of steam piping of a power plant
US20160138428A1 (en) * 2014-11-13 2016-05-19 General Electric Company System and method for heat recovery and steam generation in combined cycle systems
CN105986845A (zh) * 2015-02-15 2016-10-05 深圳市能源环保有限公司 一种汽轮机蒸汽管路系统

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111561360B (zh) * 2020-05-09 2023-03-21 广西电网有限责任公司电力科学研究院 一种热电联产机组运行区域的测试方法及系统

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3175367A (en) * 1962-08-08 1965-03-30 Foster Wheeler Corp Forced flow vapor generating unit
US3183896A (en) * 1964-01-15 1965-05-18 Foster Wheeler Corp Separating heater
US3220193A (en) * 1961-01-06 1965-11-30 Gilbert Associates Devices for improving operating flexibility of steam-electric generating plants

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3220193A (en) * 1961-01-06 1965-11-30 Gilbert Associates Devices for improving operating flexibility of steam-electric generating plants
US3175367A (en) * 1962-08-08 1965-03-30 Foster Wheeler Corp Forced flow vapor generating unit
US3183896A (en) * 1964-01-15 1965-05-18 Foster Wheeler Corp Separating heater

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4311013A (en) * 1979-02-27 1982-01-19 Hitachi, Ltd. Method of controlling condensation system of steam plant
US4665706A (en) * 1981-05-12 1987-05-19 The Babcock & Wilcox Company Control system for variable pressure once-through boilers
US5390631A (en) * 1994-05-25 1995-02-21 The Babcock & Wilcox Company Use of single-lead and multi-lead ribbed tubing for sliding pressure once-through boilers
US20100107636A1 (en) * 2008-10-30 2010-05-06 General Electric Company Provision for rapid warming of steam piping of a power plant
US7987675B2 (en) * 2008-10-30 2011-08-02 General Electric Company Provision for rapid warming of steam piping of a power plant
CN101725381B (zh) * 2008-10-30 2013-03-27 通用电气公司 用于发电设备的蒸汽管道的快速加热的设备和方法
US20160138428A1 (en) * 2014-11-13 2016-05-19 General Electric Company System and method for heat recovery and steam generation in combined cycle systems
US9470112B2 (en) * 2014-11-13 2016-10-18 General Electric Company System and method for heat recovery and steam generation in combined cycle systems
CN105986845A (zh) * 2015-02-15 2016-10-05 深圳市能源环保有限公司 一种汽轮机蒸汽管路系统

Also Published As

Publication number Publication date
DK114780B (da) 1969-08-04
NL6513736A (da) 1966-04-25
BE671323A (da) 1966-02-14
SE316783B (da) 1969-11-03
GB1102168A (en) 1968-02-07

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