US3850148A - Forced through-flow steam generator having a superimposed forced circulation - Google Patents

Forced through-flow steam generator having a superimposed forced circulation Download PDF

Info

Publication number
US3850148A
US3850148A US00369193A US36919373A US3850148A US 3850148 A US3850148 A US 3850148A US 00369193 A US00369193 A US 00369193A US 36919373 A US36919373 A US 36919373A US 3850148 A US3850148 A US 3850148A
Authority
US
United States
Prior art keywords
flow
feed
water
working fluid
superheaters
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.)
Expired - Lifetime
Application number
US00369193A
Other languages
English (en)
Inventor
F Laubli
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.)
Sulzer AG
Original Assignee
Sulzer AG
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 Sulzer AG filed Critical Sulzer AG
Application granted granted Critical
Publication of US3850148A publication Critical patent/US3850148A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • F22B35/10—Control systems for steam boilers for steam boilers of forced-flow type of once-through type
    • F22B35/104—Control systems by injecting water
    • 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
    • F22B35/10—Control systems for steam boilers for steam boilers of forced-flow type of once-through type
    • F22B35/101—Control systems for steam boilers for steam boilers of forced-flow type of once-through type operating with superimposed recirculation during starting or low load periods, e.g. composite boilers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22G—SUPERHEATING OF STEAM
    • F22G5/00—Controlling superheat temperature
    • F22G5/20—Controlling superheat temperature by combined controlling procedures

Definitions

  • ABSTRACT An injection line is branched off from a point downstream of the circulating pump to inject water into a point between two of the superheaters. The flow rate in this line is measured and a corresponding signal is sent to a controller for regulating the amount of feed water delivered to the steam generator. This signal is superimposed on a signal of opposite sign derived from a measurement of the feed water rate downstream of the feed pump.
  • evaporator is defined in the above application as including the equivalent components in supercritical steam generators, usually afforded by the tubes of the combustion chamber walls, and the same definition is hereby adopted for the present specification. The reason for this definition is that the present invention is applicable to supercritical steam generators for which the term evaporator is not wholly appropriate.
  • An advantage of the method described in the above application is that the pressure drop across the evaporator is available for water injection so that an adequate pressure difference is available for injection even under conditions of part load.
  • the rate of flow of feed water is controlled so as to tend to maintain a set value.
  • disturbances can arise if a change in temperature in the superheated steam leads to an alteration in the injection flow rate.
  • Such a disturbance can be corrected only slowly by the system described in that application.
  • This is particularly serious if the rate of injection is controlled by a controller having integral action and the separator is operated under dry conditions. In this case, it is possible for the controller to change the rate of injection to the limit of the regulating range so that control is lost. Although'this could be avoided by employing a controller without any integral action, this is usually undesirable.
  • the invention provides a forced throughflow steam generator having a superimposed circulation with a means of regulating the feed water flow in dependence on the delivered flow rate and an injection rate.
  • the steam generator includes a main working fluid path comprising, in series, a feed pump, a circulation pump, an evaporator (as herein defined), a water/- steam separator and at least two superheaters.
  • the means for regulating the feed water flow includes a first device for measuring the flow delivered by the feed pump, a second device for measuring the flow in the water injection line and a controller for adjusting the feed water flow delivered by the feed pump in dependence upon the flow rate measured by the first device so as to tend to maintain thefeed water flow at a set value and in dependence upon the flow rate measured by the second device so as to tend to increase the feed water flow as the flow rate measured by the second device increases.
  • the additional control on the feed water flow rate in dependence upon the rate of injection reduces, or avoids, the difficulty of correcting the injection rate should a change in temperature in the superheated steam occur.
  • the steam generator can be operated satisfactorily with the injection flow rate under the control of a controller having integral action. Best results are obtained when the controller is suplied with signals from the first device and the second device which are to the same scale.
  • FIG. l diagrammatically illustrates a steam generator according to the invention in which the injection flow rate at one injection point is used to control feed water flow rate
  • FIG. 2 diagrammatically illustrates a modified steam generator according to the invention in which the injection flow rate at two injection points is used to control the feed water flow rate.
  • the forced through-flow steam generator includes a main working fluid path having a feed pump 1, a feed valve 2, a station 3 at which the feed water flow rate is measured by any suitable means, an economiser 4, a circulating pump 5, an evaporator 6, a water/steam separator 7, a superheater 8, an injection point 9, a superheater 10, an injection point 11, a final superheater l2 and a live steam line 13, all of which are connected in series in the order stated.
  • a connecting line 20 forming a circulating path with a non-retum valve 21 leads from the separator 7 to a return point 22 which is located upstream of the circulating pump 5.
  • An injection water duct 26 branches off from a point 25 upstream of the station 3 for measuring the feed water flow rate and leads via an injection valve 27 to the injection point 11.
  • the water separator 7 is provided with a level measuring element 30, the output of which is connected to the left-hand input of a changeover switch 31.
  • a temperature sensor 32 is provided at the downstream end of the first superheater 8 and has an output connected to the right-hand input of the changeover switch 31.
  • the output of the changeover switch 31 acts via a controller 36 with proportional plus integral action as a set value on a feed controller 37.
  • the feed controller 37 is also supplied with a measured value comprising the output of a measuring device or apparatus 38 for measuring the feed water flow rate at the station 3.
  • the output of the feed controller 37 acts on the feed valve 2 in the sense that a rise in the measured feed water flow rate will tend to move the feed valve 2 in the closing direction and a rise of level in the water separator 7 or a reduction of temperature at the end of the superheater 8 will tend to move the feed valve 2 in the closing direction.
  • the feed regulator 37 is additionally connected via a conductor 40 to a load signal generator 41 which also supplies a load-dependent set value signal to the PI controller 36 via a conductor 42.
  • the load signal generator 41 also acts on a servomotor 34 which operates the changeover switch 31 by means of a rod 35, as is known, so that, at low loads, the switch 31 transmits the signal formed by the level measuring element 30 to the controller 36 but, at high loads, the switch 31 transmits the signal from the temperature sensor 32 to the controller 36.
  • the load transmitter 41 is constructed so that the set value signal supplied to the controller 36 via the conductor 42 is simultaneously and suitably changed in the course or such a changeover operation.
  • An injection line 50 branches off from the line joining the economiser 4 to the evaporator 6 at a point 55 which is downstream of the circulating pump 5.
  • the injection line 50 rejoins the main working medium circuit at a point 9 between the first two superheaters 8 and 10 and contains a valve 51 which is conventionally actuated via a controller 53 with proportional plus integral action by a temperature measuring device 52 at the downstream end of the superheater 10.
  • the injection line 50 contains a device 60 for measuring the flow rate of the injected water.
  • the output of the flow rate measuring device 60 acts via a signal line 61 on the feed regulator 37 on the same scale but in the opposite sense a to the measured value signal of the means 38 for measuring the feed water flow rate.
  • the steam generator shown in FIG. 1 is suitable for sliding-pressure operation, the set value for the feed water "controller 37 being defined in the lower load range by the water level in the water separator 7, but in the upper load range in which the separator is operated dry by the temperature of the superheated steam measured at the end of the first superheater 8.
  • the line 50 for the injection point 9 is branched off from the delivery of the circulating pump 5 so that a sufiiciently high injection pressure is ensured even at very low load.
  • the pressure drop resulting from the increased flow rate across the evaporator 6 and the inlet superheater 8 is sufficient to provide an adequate injection pressure.
  • Influencing the feed controller 37 with a signalrepresenting the injected water flow rate measured in the injection line 50 ensures that any change of injected water flow rate immediately results in an equal change of feed water flow rate.
  • the evaporator 6 is protected against any disturbance of the inlet flow rate.
  • the forced throughflow steam generator with superimposed circulation differs from that of FIG. 1 in that both injection points 9 and 11 are connected to the same injection line which is branched off at the point from the delivery of the circulating pump 5.
  • the measured value supplied to the feed controller 37 is delivered by an integral-action controller 36' instead ofby a PI controller 36.
  • This integral-action controller 36' is arranged to regulate the temperature difference measured by thermocouples which are disposed upstream and downstream of the injection point 11 as shown.
  • Supplying the feed regulator 37 with the output signal from the injected water flow measuring means in this embodiment also prevents the injection controller 53 from running off to the limit of the regulating range in the event of a change in the injected water flow rate and prevents any change of injected water flow rate from causing any disturbance in the feed rate to the evaporator.
  • a forced through-flow steam generator comprising a main working fluid path including, in series, a feed pump, a feed valve, a circulation pump, an evaporator, a water/steam separator and at least two superheaters;
  • a circulation path including a line extending from said separator to said main working fluid path upstream of said circulation pump;
  • a water injection line extending from said main working fluid path between'said circulation pump and said evaporator to an injection point in said main working fluid path between'said superheaters, and an injection valve in said line for controlling the flow therethrough in response to the temperature downstream of said superheaters;
  • means for regulating the feed water flow including a firstdevice for measuring the flow delivered downstream of said feed pump, a second device for measuring the flow in said water injection line, and a controller connected to each said device and to said feed valve for adjusting the feed water flow from said feed pump in dependence upon the flow rate measured by said first device to tend to maintain the feed water flow at a set value and in dependence upon the flow rate measured by said second device to tend to increase the feed water flow as the flow rate measured by said second device increases.
  • a forced through-flow steam generator as set forth in claim 1 which further includes a level measuring element connected to said separator for measuring the level of water therein and emitting a signal in response thereto, a temperature sensor downstream of the first of said superheaters for measuring the temperature of steam therebetween and emitting a signal in response thereto, a proportional plus integral action controller selectively connected to one of said element and sensor to receive a signal therefrom, and a load transmitter connected to said latter controller to deliver a set value signal thereto for comparison with the received signal, said latter controller being connected to said first controller to deliver a set value thereto corresponding to the compared signals in said latter controller for comparison with signals received from said devices.
  • a method of controlling a forced through-flow steam generator having a main working fluid path including, in series, a feed pump, a feed valve, a circulation pump, an evaporator, a water/steam separator and at least two superheaters; a circulation path including a line extending from said separator to said main working fluid path upstream of said circulation pump; a water injection line extending from said main working fluid path between said circulation pump and said evaporator to an injection point in said main working fluid path between said superheaters, and an injection valve in said line for controlling the flow therethrough in response to the temperature downstream of said superheaters', and comprising the steps of measuring the flow delivered by said feed pump; measuring the flow in said water injection line; and

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)
US00369193A 1972-06-12 1973-06-12 Forced through-flow steam generator having a superimposed forced circulation Expired - Lifetime US3850148A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH868872A CH552771A (de) 1972-06-12 1972-06-12 Zwangdurchlaufdampferzeuger.

Publications (1)

Publication Number Publication Date
US3850148A true US3850148A (en) 1974-11-26

Family

ID=4343563

Family Applications (1)

Application Number Title Priority Date Filing Date
US00369193A Expired - Lifetime US3850148A (en) 1972-06-12 1973-06-12 Forced through-flow steam generator having a superimposed forced circulation

Country Status (9)

Country Link
US (1) US3850148A (fr)
JP (1) JPS542323B2 (fr)
BE (1) BE800540A (fr)
CH (1) CH552771A (fr)
FR (1) FR2188790A5 (fr)
GB (1) GB1425058A (fr)
IT (1) IT990630B (fr)
NL (1) NL156502B (fr)
SE (1) SE379238B (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4144846A (en) * 1977-09-27 1979-03-20 Sulzer Brothers Ltd. Forced-flow steam generator
US4473036A (en) * 1982-12-28 1984-09-25 The United States Of America As Represented By The United States Department Of Energy Means and method for vapor generation
US20100263607A1 (en) * 2009-04-16 2010-10-21 Andrew Travaly Desuperheater for a steam turbine generator
WO2012034876A3 (fr) * 2010-09-13 2013-02-28 Siemens Aktiengesellschaft Procédé de régulation d'une augmentation de puissance à court terme d'une turbine à vapeur
WO2012045730A3 (fr) * 2010-10-05 2013-03-07 Siemens Aktiengesellschaft Procédé pour réguler une augmentation de puissance à court terme d'une turbine à vapeur
US20130247845A1 (en) * 2010-12-27 2013-09-26 Mitsubishi Heavy Industries, Ltd. Heat recovery and utilization system

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH609138A5 (en) * 1976-05-14 1979-02-15 Sulzer Ag Forced-flow steam generator
FR2401380A1 (fr) * 1977-08-23 1979-03-23 Sulzer Ag Generateur de vapeur a circulation forcee
TW212826B (fr) * 1991-11-28 1993-09-11 Sulzer Ag

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3089308A (en) * 1959-07-03 1963-05-14 Siemens Ag Regulating system for steam power plants with forced-flow boilers
US3134367A (en) * 1957-07-31 1964-05-26 Siemens Ag Regulating system for once-through boilers
US3175541A (en) * 1963-03-25 1965-03-30 Combustion Eng Automatic feedwater control system and method of operating same
US3216403A (en) * 1962-08-27 1965-11-09 Burmeister & Wains Mot Mask Method for controlling a once-through boiler and controlling system for performing the method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3134367A (en) * 1957-07-31 1964-05-26 Siemens Ag Regulating system for once-through boilers
US3089308A (en) * 1959-07-03 1963-05-14 Siemens Ag Regulating system for steam power plants with forced-flow boilers
US3216403A (en) * 1962-08-27 1965-11-09 Burmeister & Wains Mot Mask Method for controlling a once-through boiler and controlling system for performing the method
US3175541A (en) * 1963-03-25 1965-03-30 Combustion Eng Automatic feedwater control system and method of operating same

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4144846A (en) * 1977-09-27 1979-03-20 Sulzer Brothers Ltd. Forced-flow steam generator
US4473036A (en) * 1982-12-28 1984-09-25 The United States Of America As Represented By The United States Department Of Energy Means and method for vapor generation
US20100263607A1 (en) * 2009-04-16 2010-10-21 Andrew Travaly Desuperheater for a steam turbine generator
US8347827B2 (en) * 2009-04-16 2013-01-08 General Electric Company Desuperheater for a steam turbine generator
WO2012034876A3 (fr) * 2010-09-13 2013-02-28 Siemens Aktiengesellschaft Procédé de régulation d'une augmentation de puissance à court terme d'une turbine à vapeur
JP2013537271A (ja) * 2010-09-13 2013-09-30 シーメンス アクチエンゲゼルシヤフト 蒸気タービンの短期間の出力増大を調節するための方法
WO2012045730A3 (fr) * 2010-10-05 2013-03-07 Siemens Aktiengesellschaft Procédé pour réguler une augmentation de puissance à court terme d'une turbine à vapeur
CN103249918A (zh) * 2010-10-05 2013-08-14 西门子公司 短期提高汽轮机功率的控制方法
US9080465B2 (en) 2010-10-05 2015-07-14 Siemens Aktiengesellschaft Method for controlling a short-term increase in power of a steam turbine
CN103249918B (zh) * 2010-10-05 2016-08-10 西门子公司 短期提高汽轮机功率的控制方法
US20130247845A1 (en) * 2010-12-27 2013-09-26 Mitsubishi Heavy Industries, Ltd. Heat recovery and utilization system
US9803853B2 (en) * 2010-12-27 2017-10-31 Mitsubishi Hitachi Powers Systems, Ltd. Heat recovery and utilization system

Also Published As

Publication number Publication date
NL156502B (nl) 1978-04-17
BE800540A (fr) 1973-12-06
FR2188790A5 (fr) 1974-01-18
SE379238B (fr) 1975-09-29
CH552771A (de) 1974-08-15
JPS4962802A (fr) 1974-06-18
GB1425058A (en) 1976-02-18
JPS542323B2 (fr) 1979-02-06
NL7208960A (fr) 1973-12-14
IT990630B (it) 1975-07-10

Similar Documents

Publication Publication Date Title
US3850148A (en) Forced through-flow steam generator having a superimposed forced circulation
KR101206711B1 (ko) 드럼형 보일러의 드럼 수위 제어 장치 및 그 방법
GB1387716A (en) Method and apparatus for controlling a steam generator
US3780705A (en) Method of controlling the feed of forced circulation steam generators
GB1133148A (en) Steam turbine power system and method of operating the same
US4031863A (en) Process and a control system for controlling the exit temperature of vapor flowing through a contact heating surface of a vapor generator
US3769942A (en) Method of regulating the temperature of superheated steam in a steam generator
CA1236898A (fr) Regulateur de la variable de traitement d'un ecoulement
US4144846A (en) Forced-flow steam generator
US4080789A (en) Steam generator
GB1207366A (en) Forced flow steam generators
US4825654A (en) Steam plant and method of controlling same
US2412739A (en) Apparatus for steam generator control
GB1063236A (en) A steam boiler and turbine installation
US3412714A (en) Control system for once-through type boiler
GB1154476A (en) An Installation comprising a Steam Boiler and Control Means For It
GB937168A (en) Steam temperature regulation in steam generators
US3260246A (en) Regulating arrangement for forced flow type boiler
US3665895A (en) Process for variable-pressure operation of a forced-flow vapor generator
US3690303A (en) Forced circulating steam generator and method of generating steam
GB831175A (en) Apparatus and method for controlling a forced flow once-through steam generator
GB858928A (en) Method of and apparatus for discharging liquid working medium out of the separator of a forced through-flow steam generator
GB926949A (en) Regulation of forced-flow once-through steam generators
US3338054A (en) Method and apparatus for increasing control response of a vapor generator
FR2401380A1 (fr) Generateur de vapeur a circulation forcee