US3370573A - Start-up system for combined circulation steam generator - Google Patents

Start-up system for combined circulation steam generator Download PDF

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Publication number
US3370573A
US3370573A US600905A US60090566A US3370573A US 3370573 A US3370573 A US 3370573A US 600905 A US600905 A US 600905A US 60090566 A US60090566 A US 60090566A US 3370573 A US3370573 A US 3370573A
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United States
Prior art keywords
pressure
flow
fluid
steam
steam generator
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Expired - Lifetime
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US600905A
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English (en)
Inventor
Frederick J Hanzalek
Alwin W Ambrose
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Combustion Engineering Inc
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Combustion Engineering Inc
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Publication date
Application filed by Combustion Engineering Inc filed Critical Combustion Engineering Inc
Priority to US600905A priority Critical patent/US3370573A/en
Priority to GB51632/67A priority patent/GB1195260A/en
Priority to FR1554796D priority patent/FR1554796A/fr
Priority to SE16195/67A priority patent/SE318893B/xx
Priority to BE707074D priority patent/BE707074A/xx
Priority to DE19671576862 priority patent/DE1576862B2/de
Priority to CH1674267A priority patent/CH485984A/de
Priority to ES347912A priority patent/ES347912A1/es
Priority to NL6716498A priority patent/NL6716498A/xx
Application granted granted Critical
Publication of US3370573A publication Critical patent/US3370573A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • F22B35/08—Control systems for steam boilers for steam boilers of forced-flow type of forced-circulation type
    • F22B35/083—Control systems for steam boilers for steam boilers of forced-flow type of forced-circulation type without drum, i.e. without hot water storage in the boiler
    • 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
    • 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
    • F22B29/12—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 operating with superimposed recirculation during starting and low-load periods, e.g. composite boilers

Definitions

  • FIG. 2 ALWlN w. AMBROSE AGENT United States Patent C 3,370,573 START-UP SYSTEM FOR COMBINED CIRCULA- TRON STEAM GENERATOR Frederick J. Hanzalek, Suflield, and Alwin W. Ambrose,
  • the invention relates to a method and system of operating, and more specifically, of starting a high pressure forced through-flow steam generator of the type commonly referred to as a combined circulation steam generator.
  • a combined circulation steam generator for a more detailed description of the characteristics of a combined circulation steam generator, reference may be had to US. Patent No. 3,194,217 issued to H. A. Grabowski on July 13, 1965, and entitled Boiler Cleanup Method for Combined Circulation Steam Generator.
  • boiler throttle valve or BT valve When starting a forced through-flow high pressure steam generator, it is customary to separate the steam generating portion of the working fluid path from the steam heating or superheating portion by a so-called boiler throttle valve or BT valve although the present invention is also applicable to units which do not have such a valve.
  • the boiler is filled with the working fluid up to the BT valve which is closed and the pressure is raised to near normal operating pressure or other suitable pressure by the feed pump.
  • the volume of the fluid expands due to increase in temperature, which expansion causes an overflow of the fluid to the condenser or to other low pressure portion of the feed cycle through the so-called boiler extraction valve or BE valve provided in the fluid flow path downstream of the furnace wall tubes.
  • a flow of the fluids through the furnace tubes and the BE valve of approximately 30% of the rated maximum flow must be maintained to protect these furnace tubes against excessive heat during the start-up operation.
  • FIG. 1 depicts a diagrammatic representation of a forced through-flow steam generating plant of the combined circulation type employing the herein disclosed inventive swell relieving means at the cold end of the steam generator;
  • FIG. 2 is a diagrammatic representation of a portion of the steam generating plant of FIG. 1, however showing the swell relieving means being combined with the feedwater pump recirculating or bleed-off line;
  • FIG. 3 is a typical pressure reduction device of the capillary tube type.
  • FIG. 1 shows a forced through-flow steam generator generally indicated by the numeral 10.
  • the steam generator is adapted to be fired in any conventional manner by appropriate firing means (not shown), and to deliver high pressure high temperature steam to a steam utilization device such as steam turbine 12.
  • Condensate pump 14 and feed pumps 16 and 18 force water or working fluid from a source of supply such as condenser 20, by way of demineralizer 22, low pressure feedwater heater 24, deaerator 26, intermediate pressure feedwater heater 27 into a first fluid flow section A which may comprise high pressure feedwater heater 28.
  • Steam generator 10 includes a second fluid flow section B and a third fluid flow section C which are interconnected with fluid flow section A for series flow therethrough as shown.
  • Flow section B preferably includes an economizer 30 and furnace wall tubes 32.
  • Flow section C includes one or more superheater sections 34. Interpositioned between the flow sections B and C may be interposed a so-called boiler throttling valve BT which during normal operation of the steam generator remains I fully open.
  • the feedwatcr after having been preheated in the feedwater heaters 24, 27, and 28 and economizer 30, is converted into steam in furnace wall tubes 32 and after passing through valve ET the steam is superheated in flow section C from whence it is delivered to turbine 12 during normal operation of the steam generator.
  • valve ET When starting up the steam generator and turbine 12 valve ET is normally closed. During a later phase of the start-up operation, high pressure water at 3500 psi. pressure and 800 F. temperature, for example, is passed through conduit 35 and boiler extraction valve BE to a water and steam separator or flash tank 36 with the pressure thereby being reduced to the desired turbine start-up pressure such as 500 psi. Steam produced by flashing is separated from the water in separator 36 and flows through conduit 37 to superheater 34-tor further heating. The steam is then conducted by way of steam line 38 to turbine 12 for the heating, rolling, and starting of the turbine. The water separated from the steam in separator 36 is generally conducted to the condenser by way of pipe 39, or to any other feedwater storage vessel.
  • the invention provides a method in which through flow is entirely eliminated be completely closing valve BE.
  • the quantity of the working fluid which in a combined circulation steam generator is generally recirculated around the furnace tubes 32, or the furnace tubes 32 and economizer 30, by way of recirculating conduit 49 and recirculation pump 42, must be sufficient to protect the heating surface from overheating even without any through flow.
  • the invention provides for the overflow caused by the swelling of the water during the pressure raising and heating phase, to be discharged by way of the relatively cold end of the steam generator such as through conduit 44 and one or several valves 46.
  • This conduit 44 includes a pressure breakdown device which may consist of a series of orifices 48. The pressure loss through these orifices and through conduit 44 and valves 46 is limited to such a value that flashing to steam is confined to the receiving tank, such as deaerator 26 for example.
  • the overflow may also be discharged into other portions of the feedwater system wherein a low pressure such as 5 p.s.i. prevails.
  • capillary tubing 50 as shown in FIG. 3, can be used in place of or in addition to orifices 48.
  • This tubing may consist of one or several pipes having a small diameter bore 52, and being suitable length to produce the desired pressure reduction.
  • FIG. 2 shows an embodiment of the invention wherein the overflow or swell is discharged through the bypass customarily installed in the discharge line of the boiler feed pump. It is almost common knowledge that a pump operated atshut-otf would soon overheat and seize. Accordingly, some specific means must be applied to maintain a predetermined flow through the boiler feed pump regardless of through-flow. This is acornplished by recirculating a limited quantity of fluid through bypass line 54. This bypass is located on the pump side of the .dis-
  • charge gate and check valves 56 leads to some region of low pressure in the boiler feed cycle.
  • line 54 leads to the deaerator 26.
  • the capacity of the bypass is generally such that should the demand of the boiler fall to zero or should one of the valvesbecome closed while the pump is running at full speed, the flow through the pump will not fall below the predetermined permissible minimum.
  • the overflow due to swell is discharged into the pump bypass line 54 by way of conduit 58 and valve 69.
  • the capacity of line 54 and the pressur'ebreakdown device 62 customarily used in bypass line 54, is in accordance with the invention increased to seri/e the two-fold purpose of (1) relieving the overflow due to swell of the fluid during the start-up operation, and (2) maintaining a predetermined minimum flow through thefeed pump 18 regardless of the delivery flow.
  • the pressure breakdown device can be of any suitable type such as a series of orifices 48 or capillary tubing 56.
  • a pressure breakdown device is included in said first conduit, said breakdown device comprising a plurality of orifices adapted for series flow therethrough.
  • the first fluid flow section includes a high pressure feedwater heater and the second fluid flow'section an economizer
  • the swell relieving conduit means is adapted for receiving fluid from a point of departure located in a portion of the fluid flow circuitry downstream of the feedwater heater and upstream of the economizer.
  • check valve means are provided in the fluid flow circuitry between said point of departure and the feedwater heater to prevent reverse fluid fl w back throu the feedwater heater.
  • a stop and check valve is provided between said pump means and said first fluid flow section, and a bleed-0E conduit for bleeding ofl fluid from the discharge side of the pump means upstream of said stop and check valve to said low pressure region, and wherein said first conduit establishes communication between said second portion of the circuitry and said bleed-0S conduit.
  • Apparatus according to claim 6 wherein a pressure breakdown device is included in at least one of said first circuit and said bleed-off conduit.
  • said method comprising the additional improvement step 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)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)
US600905A 1966-12-12 1966-12-12 Start-up system for combined circulation steam generator Expired - Lifetime US3370573A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US600905A US3370573A (en) 1966-12-12 1966-12-12 Start-up system for combined circulation steam generator
GB51632/67A GB1195260A (en) 1966-12-12 1967-11-13 Forced Through-Flow Steam Generator and Method of Starting the Same
SE16195/67A SE318893B (de) 1966-12-12 1967-11-24
BE707074D BE707074A (de) 1966-12-12 1967-11-24
FR1554796D FR1554796A (de) 1966-12-12 1967-11-24
DE19671576862 DE1576862B2 (de) 1966-12-12 1967-11-27 Einrichtung zum anfahren eines zwangdurchlaufdampferzeugers
CH1674267A CH485984A (de) 1966-12-12 1967-11-29 Verfahren zum Anfahren eines Zwangdurchlaufdampferzeugers
ES347912A ES347912A1 (es) 1966-12-12 1967-12-02 Un metodo y su correspondiente aparato generador de vapor de circulacion forzada, para poner en marcha el citado apa- rato.
NL6716498A NL6716498A (de) 1966-12-12 1967-12-04

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US600905A US3370573A (en) 1966-12-12 1966-12-12 Start-up system for combined circulation steam generator

Publications (1)

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US3370573A true US3370573A (en) 1968-02-27

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US600905A Expired - Lifetime US3370573A (en) 1966-12-12 1966-12-12 Start-up system for combined circulation steam generator

Country Status (9)

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US (1) US3370573A (de)
BE (1) BE707074A (de)
CH (1) CH485984A (de)
DE (1) DE1576862B2 (de)
ES (1) ES347912A1 (de)
FR (1) FR1554796A (de)
GB (1) GB1195260A (de)
NL (1) NL6716498A (de)
SE (1) SE318893B (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3774579A (en) * 1971-02-17 1973-11-27 Hitachi Ltd Method and apparatus for restarting boiler feed-water pump system
US3972193A (en) * 1975-01-02 1976-08-03 Foster Wheeler Energy Corporation Integral separator start-up system for a vapor generator with constant pressure furnace circuitry
US4232635A (en) * 1977-12-27 1980-11-11 Kraftwerk Union Aktiengesellschaft Method of improving the permissible load-varying speed of a once-through steam generator and device for performing the method
US4535593A (en) * 1981-08-28 1985-08-20 Hitachi, Ltd. Method of and apparatus for warming high-pressure feed water heaters for power plants
US5048466A (en) * 1990-11-15 1991-09-17 The Babcock & Wilcox Company Supercritical pressure boiler with separator and recirculating pump for cycling service
WO1995010733A1 (en) * 1993-10-08 1995-04-20 A. Ahlstrom Corporation Supercritical steam pressurized circulating fluidized bed boiler
US20050072153A1 (en) * 2003-10-01 2005-04-07 Baker Karl William Superheater capillary two-phase thermodynamic power conversion cycle system
US20110155347A1 (en) * 2009-12-21 2011-06-30 Alstom Technology Ltd. Economizer water recirculation system for boiler exit gas temperature control in supercritical pressure boilers
WO2014133869A1 (en) * 2013-03-01 2014-09-04 Conocophillips Company Throttling boiler for fouling mitigation

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19544226B4 (de) * 1995-11-28 2007-03-29 Alstom Kombianlage mit Mehrdruckkessel

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3174288A (en) * 1959-10-16 1965-03-23 Sulzer Ag Steam power plant
US3194218A (en) * 1963-03-25 1965-07-13 Combustion Eng Apparatus and method for starting forced flow once-through steam generating power plant

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3174288A (en) * 1959-10-16 1965-03-23 Sulzer Ag Steam power plant
US3194218A (en) * 1963-03-25 1965-07-13 Combustion Eng Apparatus and method for starting forced flow once-through steam generating power plant

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3774579A (en) * 1971-02-17 1973-11-27 Hitachi Ltd Method and apparatus for restarting boiler feed-water pump system
US3972193A (en) * 1975-01-02 1976-08-03 Foster Wheeler Energy Corporation Integral separator start-up system for a vapor generator with constant pressure furnace circuitry
US4099384A (en) * 1975-01-02 1978-07-11 Foster Wheeler Energy Corporation Integral separator start-up system for a vapor generator with constant pressure furnace circuitry
US4232635A (en) * 1977-12-27 1980-11-11 Kraftwerk Union Aktiengesellschaft Method of improving the permissible load-varying speed of a once-through steam generator and device for performing the method
US4535593A (en) * 1981-08-28 1985-08-20 Hitachi, Ltd. Method of and apparatus for warming high-pressure feed water heaters for power plants
US5048466A (en) * 1990-11-15 1991-09-17 The Babcock & Wilcox Company Supercritical pressure boiler with separator and recirculating pump for cycling service
WO1995010733A1 (en) * 1993-10-08 1995-04-20 A. Ahlstrom Corporation Supercritical steam pressurized circulating fluidized bed boiler
US5474034A (en) * 1993-10-08 1995-12-12 Pyropower Corporation Supercritical steam pressurized circulating fluidized bed boiler
US20050072153A1 (en) * 2003-10-01 2005-04-07 Baker Karl William Superheater capillary two-phase thermodynamic power conversion cycle system
US6918254B2 (en) * 2003-10-01 2005-07-19 The Aerospace Corporation Superheater capillary two-phase thermodynamic power conversion cycle system
US20110155347A1 (en) * 2009-12-21 2011-06-30 Alstom Technology Ltd. Economizer water recirculation system for boiler exit gas temperature control in supercritical pressure boilers
US9696027B2 (en) * 2009-12-21 2017-07-04 General Electric Technology Gmbh Economizer water recirculation system for boiler exit gas temperature control in supercritical pressure boilers
WO2014133869A1 (en) * 2013-03-01 2014-09-04 Conocophillips Company Throttling boiler for fouling mitigation

Also Published As

Publication number Publication date
FR1554796A (de) 1969-01-24
NL6716498A (de) 1968-06-13
DE1576862A1 (de) 1970-10-01
CH485984A (de) 1970-02-15
DE1576862B2 (de) 1971-09-23
SE318893B (de) 1969-12-22
BE707074A (de) 1968-05-24
ES347912A1 (es) 1969-06-01
GB1195260A (en) 1970-06-17

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