US3464393A - Steam generator with forced circulation - Google Patents

Steam generator with forced circulation Download PDF

Info

Publication number
US3464393A
US3464393A US678657A US3464393DA US3464393A US 3464393 A US3464393 A US 3464393A US 678657 A US678657 A US 678657A US 3464393D A US3464393D A US 3464393DA US 3464393 A US3464393 A US 3464393A
Authority
US
United States
Prior art keywords
medium
steam
pressure
superheater
evaporation
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
US678657A
Other languages
English (en)
Inventor
Lars Axel A Chambert
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.)
Svenska Maskinverken AB
Original Assignee
Svenska Maskinverken AB
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 Svenska Maskinverken AB filed Critical Svenska Maskinverken AB
Application granted granted Critical
Publication of US3464393A publication Critical patent/US3464393A/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
    • F22B29/00—Steam boilers of forced-flow type
    • F22B29/02—Steam boilers of forced-flow type of forced-circulation type
    • F22B29/023—Steam boilers of forced-flow type of forced-circulation type without drums, i.e. without hot water storage in the boiler
    • F22B29/026—Steam boilers of forced-flow type of forced-circulation type without drums, i.e. without hot water storage in the boiler operating at critical or supercritical pressure

Definitions

  • This invention relates to a steam generator with forced circulation which is adapted to work up to an optional pressure both below and above the critical point of the working medium.
  • the medium is heated in channels or tubes which are heated from the outside.
  • a division can be made between the portion which heats the medium, so that evaporation is effected (boiling area), or in overcritical operation to a point close to the critical point, and that portion of the apparatus which generally is defined as superheater and which heats the medium to the desired final condition.
  • the present construction refers to the portion which heats the medium to evaporation or to a point close to the critical point of the medium.
  • this portion is referred to as the evaporation portion of the apparatus.
  • Alternative I illustrates a straight flow with pre-heater a, evaporation portion b and superheater c, which substantially are comprised also in Alternative II, in the system of which, however, a small number of steam separators d are incorporated to which the collected medium flow from portion b is introduced.
  • the desired minimum flow can be obtained in that the medium, via valves and pumps, is returned from a point between b and c to the inlet side.
  • the medium has in Alternative I a direct flow and in Alternative II a substantially direct flow, a smaller amount being returned via the steam separator.
  • the steam separator can be designed as a cyclone separator with level control for conducting away separated medium.
  • the steam separation normally takes place in a horizontally mounted pressure vessel e, a drum, and separated medium which is not evaporated is returned by natural circulation (IIIb) or by one or several pumps f to the inlet or before the evaporation portion (IIIa)
  • This principle is applied in the known drum boiler.
  • the steam separation in the shown pressure vessel e or dome can take place in a number of small cyclones or within the drum.
  • the control of the medium flow supplied is made via level determination in the said pressure vessel.
  • evaporation takes place in a usual way in the portion marked b.
  • the steam separation takes place in a plurality of small cyclones g each of which is connected to groups of evaporation tubes.
  • the separated medium is recirculated to a mixing vessel h.
  • the drive force for the medium is obtained by a pump means i or possibly by natural circulation.
  • the incoming medium is controlled on the basis of a level determination or of another method in the mixing vessel, so that there is a sufficient amount of medium for ensuring the function of the apparatus.
  • the steam separator function thus, is separated in the way described from that portion of the system which primarily serves for mixing the incoming and the recirculated medium and via measuring devices to control the flow of incoming medium.
  • the steam separation can take place in a point very close to the evaporation portion.
  • the introduction of the principle described, with a plurality of steam separators, implies that the great pressure vessel, the drum, and certain collecting headers can be replaced by smaller mixing vessels plus the steam separators.
  • the necessary flow area are relatively small compared with the conventional drum boiler, a.o'., for the reason that there the entire medium flow from the evaporation portion must be introduced into the drum.
  • the system permits the mass velocities required for stable heat transfer conditions to be chosen independently of the load and pressure, and the minimum load can be adjusted to the flow zero.
  • the maximum operation pressure can be chosen to amount up to and beyond the critical point.
  • FIGURES 2-6 The system and a type of steam separator are described in the following with reference to the drawing, FIGURES 2-6.
  • FIG. 2 shows a wiring diagram for a steam generating system according to the invention idea.
  • FIG. 3 shows a longitudinal section through a cyclone separator.
  • FIG. 4 shows in a horizontal View the cyclone separator according to FIG. 3.
  • FIG. 5 shows a section along AA in FIG. 3.
  • FIG. 6 shows a section along B--B in FIG. 5.
  • FIG. 2 an embodiment of the invention in question is shown in a wiring diagram.
  • the system of evaporation areas which encloses the furnace resembles in principle 3 known constructions and comprises upright furnace tubes 1. At the outlets of these tubes are mounted a relatively great number of steam separators 2.
  • a conventional starting and a bottom blowing system 3 and 4 respectively can, as shown, be built into the system.
  • the said separators can be designed, for example, according to FIGS. 3-6 which show a selected embodiment in which the tubes or channels for the partially evap. orated medium coming from the furnace area can be connected directly to the steam separator.
  • FIGS. 3-6 show a selected embodiment in which the tubes or channels for the partially evap. orated medium coming from the furnace area can be connected directly to the steam separator.
  • the medium separated in the steam separators 2 flows back to a mixing vessel 5 from the steam separators either in separate channels 6 or in one channel common to several separators.
  • the separated steam flows via usually a plurality of tubes 7 from the separators to the inlet in the superheater portions which in the embodiment shown comprises the superheaters 8, 9 and 10.
  • the recirculated medium separated in the separators 2 flows back to the mixing vessel 5 of which one or several are comprised in the apparatus, where it is mixed with the incoming medium and from where it is returned to the evaporation elements 1 by the shown pump means which, for example, is constructed as circulation pump 11 driven by an electromotor.
  • the mixing vessel can be designed, for example, as a vertical container where at subcritical operation the level is maintained substantially at or below the level of the separators.
  • the admixing of new introduced medium can entirely or partially take place in the container, but always before the evaporation area.
  • the mixing vessel is provided for pressure equalization in a suitable way with a connection 12 to a point before the superheater 8. New introduced medium is preheated in a preheater 13 prior to the mixing with circulating medium.
  • the steam separation in the described cyclones 2 is a self-adjusting process.
  • a considerable problem, however, is the level adjusting or control of the mass contents in the mixing vessel 5.
  • the medium supplied can be admixed in this vessel, which means that the vessel possibly contains medium in homogenous phase but of different temperatures, according to load etc., medium in two phases with liquid phase of saturation temperature, but also liquid phase of a lower temperature.
  • the mass contents can be measured in different ways.
  • One example is the direct measuring of the Weight of the mixing vessel.
  • the stop and control device according to the present invention has been placed after the first superheater portion 8.
  • the device comprises control valves 16, one valve for every duct, for controlling the pressure.
  • a temperature control by injection coolers 17 is arranged.
  • Such coolers are mounted also between the second and the third superheater 9 and 10 respectively.
  • the evaporation portion can be started with these valves closed, for avoiding condensate formation in cold superheater elements.
  • the point chosen is in most cases the first point where the medium flow is united to one or two collected medium flows before the injection place shown.
  • the device in combination with suitable temperature control, permits the construction data of the superheater to be chosen in an optimal way. This implies a.o. that the pressure in the superheater portions 9 and 10 can be limited to the values permitted by the prevailing feed temperature, which is of interest a.o. at rapid load decreases at the turbine unit.
  • the transition from subcritical to supercritical operation can be carried out in steps, in that first the pressure in the evaporation portion and superheater portion before the control valve of the latter is increased to the supercritical range, and thereafter the pressure in the superheater portions 9 and 10.
  • control valve in combination with the subsequent temperature controls, can be adjusted such that the stresses in the superheaters are kept under control.
  • the described effect is utilized advantageously so that at working pressures exceeding the chosen construction pressure of the superheater, the temperature is lowered below the construction temperature, whereby a detrimental effect on the life of such a mode of operation is avoided.
  • FIG. 2 shows in addition to the aforementioned means also, as in conventional installations, an intercooler 18, low-pressure turbine 19, condenser 20 and an economizer 13.
  • FIGS. 3-6 a cyclone separator is shown which comprises a container 21, in the casing of which a plurality of inlets 22 for partially evaporated medium are provided. It appears from FIG. 5 which shows a section AA in FIG. 3, that the inlets 22 are arranged tangentially by a special nozzle insert 23. The cross-sectional shape of the insert 23 is shown in FIG. 6 which is a crosssection along the line B-B in FIG. 5. The steam is conducted away in usual manner in the cyclone upwardly through the nozzle 24, while the water follows the inner walls and is led off at the bottom, see the arrow 25. As appears from FIGS. 3 and 4 which show a horizontal view of the cyclone, a great number of inlet pipes 26 are connected to different points in the cyclone casing. This contributes substantially to a high cyclone elfect.
  • each said steam separator being directly connected between References Cited sa d steam generating tube of said evaporator and UNITED STATES PATENTS said preheater, a mixing vessel, 2,170,342 8/1939 Bailey.
  • said return tubes of said steam separators being con- 3,021,824 2/1962 PTOfOS- nected to said mixing vessel, 5 3,134,367 5/ 1964 Hallethe output of said preheater also being connected to 3,205,868 9/ 1965 schwarz' said mixing vessel FOREIGN PATENTS and means for malntalnlng the amount of said medium in said vessel substantially at a predetermined m 770091 3/1957 Great Bntam' constant value.
  • each said steam separator is a cyclone-type separator.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Cyclones (AREA)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)
US678657A 1966-10-28 1967-10-27 Steam generator with forced circulation Expired - Lifetime US3464393A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE14839/66A SE312563B (en)) 1966-10-28 1966-10-28

Publications (1)

Publication Number Publication Date
US3464393A true US3464393A (en) 1969-09-02

Family

ID=20299756

Family Applications (1)

Application Number Title Priority Date Filing Date
US678657A Expired - Lifetime US3464393A (en) 1966-10-28 1967-10-27 Steam generator with forced circulation

Country Status (5)

Country Link
US (1) US3464393A (en))
CH (1) CH475024A (en))
DE (1) DE1576855A1 (en))
GB (1) GB1201783A (en))
SE (1) SE312563B (en))

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3769942A (en) * 1971-01-14 1973-11-06 Sulzer Ag Method of regulating the temperature of superheated steam in a steam generator
US3954087A (en) * 1974-12-16 1976-05-04 Foster Wheeler Energy Corporation Integral separation start-up system for a vapor generator with variable pressure furnace circuitry
US4068475A (en) * 1976-04-20 1978-01-17 Westinghouse Electric Corporation Flow control for once-through boiler having integral separators
US4205633A (en) * 1977-08-05 1980-06-03 Kraftwerk Union Aktiengesellschaft Device for separating water and steam in a once-through steam generator
US4261301A (en) * 1978-04-28 1981-04-14 Kraftwerk Union Aktiengesellschaft Temperature holding device for water collecting vessels of once-through steam generators
US5588400A (en) * 1993-02-09 1996-12-31 L. & C. Steinmuller Gmbh Method of generating steam in a forced-through-flow boiler

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009012320A1 (de) * 2009-03-09 2010-09-16 Siemens Aktiengesellschaft Durchlaufverdampfer

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2170342A (en) * 1935-12-18 1939-08-22 Babcock & Wilcox Co Vapor generator
GB770091A (en) * 1955-05-02 1957-03-13 Siemens Ag Improvements in or relating to forced-flow once-through steam boilers and methods ofremoving salt therefrom
US3021824A (en) * 1956-11-22 1962-02-20 Sulzer Ag Forced flow steam generating plant
US3134367A (en) * 1957-07-31 1964-05-26 Siemens Ag Regulating system for once-through boilers
US3205868A (en) * 1962-08-10 1965-09-14 Duerrwerke Ag Forced flow steam generator

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2170342A (en) * 1935-12-18 1939-08-22 Babcock & Wilcox Co Vapor generator
GB770091A (en) * 1955-05-02 1957-03-13 Siemens Ag Improvements in or relating to forced-flow once-through steam boilers and methods ofremoving salt therefrom
US3021824A (en) * 1956-11-22 1962-02-20 Sulzer Ag Forced flow steam generating plant
US3134367A (en) * 1957-07-31 1964-05-26 Siemens Ag Regulating system for once-through boilers
US3205868A (en) * 1962-08-10 1965-09-14 Duerrwerke Ag Forced flow steam generator

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3769942A (en) * 1971-01-14 1973-11-06 Sulzer Ag Method of regulating the temperature of superheated steam in a steam generator
US3954087A (en) * 1974-12-16 1976-05-04 Foster Wheeler Energy Corporation Integral separation start-up system for a vapor generator with variable pressure furnace circuitry
US4068475A (en) * 1976-04-20 1978-01-17 Westinghouse Electric Corporation Flow control for once-through boiler having integral separators
US4205633A (en) * 1977-08-05 1980-06-03 Kraftwerk Union Aktiengesellschaft Device for separating water and steam in a once-through steam generator
US4261301A (en) * 1978-04-28 1981-04-14 Kraftwerk Union Aktiengesellschaft Temperature holding device for water collecting vessels of once-through steam generators
US5588400A (en) * 1993-02-09 1996-12-31 L. & C. Steinmuller Gmbh Method of generating steam in a forced-through-flow boiler

Also Published As

Publication number Publication date
DE1576855A1 (de) 1970-05-06
SE312563B (en)) 1969-07-21
CH475024A (de) 1969-07-15
GB1201783A (en) 1970-08-12

Similar Documents

Publication Publication Date Title
US3789806A (en) Furnace circuit for variable pressure once-through generator
US7628124B2 (en) Steam generator in horizontal constructional form
US5159897A (en) Continuous-flow steam generator
US3972193A (en) Integral separator start-up system for a vapor generator with constant pressure furnace circuitry
US4191133A (en) Vapor generating system utilizing integral separators and angularly arranged furnace boundary wall fluid flow tubes having rifled bores
US5924389A (en) Heat recovery steam generator
US3954087A (en) Integral separation start-up system for a vapor generator with variable pressure furnace circuitry
US3108938A (en) Power plant using a steam-cooled nuclear reactor
US3464393A (en) Steam generator with forced circulation
US3175953A (en) Steam-cooled nuclear reactor power plant
US2921441A (en) Feed water preheating system for steam power plants
CN1266412C (zh) 用于产生饱和水蒸气的蒸发器和蒸发法
US3194020A (en) Method and apparatus relating to vapor generation
US5713311A (en) Hybrid steam generating system and method
US3135251A (en) Circuit for vapor generator
US3719172A (en) Boiler systems of the water tube type
US3155079A (en) Supercritical vapor generator power plant system
KR101822311B1 (ko) 폐열 증기 발생기 및 연료 예열부를 갖는 복합 화력 발전소
US3807364A (en) Mixing header
US4116168A (en) Vapor generating system utilizing integral separators and angularly arranged furnance boundary wall fluid flow tubes
US3392712A (en) Vortex desuperheater
US4325328A (en) Vapor generator having a pair of combustion chambers
US4344388A (en) Vapor generating system utilizing integral separators and angularly arranged furnace boundary wall fluid flow tubes having rifled bores
US2240100A (en) Water tube steam generator and parts thereof
US3262428A (en) Fluid operated steam generator having steam operated feedwater preheater