EP0462486A1 - Ensemble de tubes d'évaporation d'un foyer d'une chaudière à passage unique sous pression variable - Google Patents

Ensemble de tubes d'évaporation d'un foyer d'une chaudière à passage unique sous pression variable Download PDF

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Publication number
EP0462486A1
EP0462486A1 EP91109486A EP91109486A EP0462486A1 EP 0462486 A1 EP0462486 A1 EP 0462486A1 EP 91109486 A EP91109486 A EP 91109486A EP 91109486 A EP91109486 A EP 91109486A EP 0462486 A1 EP0462486 A1 EP 0462486A1
Authority
EP
European Patent Office
Prior art keywords
furnace
tubes
headers
furnace wall
variable
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.)
Withdrawn
Application number
EP91109486A
Other languages
German (de)
English (en)
Inventor
Tadashi Nagasaki Shipyard & Engine Works Gengo
Takashi Nagasaki Shipyard & Engine Works Tsukino
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.)
Mitsubishi Heavy Industries Ltd
Original Assignee
Mitsubishi Heavy Industries Ltd
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 Mitsubishi Heavy Industries Ltd filed Critical Mitsubishi Heavy Industries Ltd
Publication of EP0462486A1 publication Critical patent/EP0462486A1/fr
Withdrawn legal-status Critical Current

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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
    • F22B29/06—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
    • F22B29/061—Construction of tube walls
    • F22B29/062—Construction of tube walls involving vertically-disposed water tubes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00—Component parts or details of steam boilers
    • F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/10—Water tubes; Accessories therefor
    • F22B37/14—Supply mains, e.g. rising mains, down-comers, in connection with water tubes
    • F22B37/141—Supply mains, e.g. rising mains, down-comers, in connection with water tubes involving vertically-disposed water tubes, e.g. walls built-up from vertical tubes

Definitions

  • the present invention is directed generally to a boiler for thermal power generation, and more particularly, to an evaporating tube unit for shaping a furnace wall of a once-through boiler in which a variable-pressure operation is carried out.
  • FIG. 8 is an entire perspective view showing one example of a conventional vertical tube type variable-pressure operating once-through boiler.
  • FIG. 9 is a perspective view fully illustrating a furnace wall part thereof.
  • a multiplicity of furnace wall tubes 10, 11, the lower ends of which are connected to a lower collecting header 14, are disposed in front and in rear.
  • Furnace wall tubes 12, 13 connected to lower wall headers 15, 16 are disposed sideways.
  • the upper ends of these furnace wall tubes 10, 11, 12, 13 are connected respectively to upper headers 17, 18, 19, 20, thus constituting a furnace.
  • the furnace wall tubes 10, 11, 12, 13 are, as illustrated in FIG. 9, constructed of rifle tubes.
  • the conventional structure is such that the adjacent furnace tubes do not, through integrally welded with fins 21, communicate with each other. Internal fluids flowing in from the lower collecting header 14 and the lower wall headers 15, 16 independently run through the rifle tubes till the fluids flow in the upper headers 17, 18, 19, 20.
  • the furnace evaporating tube is composed of a single tube from an inlet of the lower part to an outlet of the uppermost part. Namely, the furnace tube is not required to be divided typically as a boiler function. For this reason, the most economical construction has hitherto been selected.
  • the furnace evaporating tube is constructed of the single tube from the inlet to the outlet. Therefore, even if the evaporating tube is designed to set the furnace outlet at a saturation temperature under in a static state, an overheating condition is developed in a dynamic state. Heat absorption within the furnace wall becomes ununiform. As a result of this, an imbalance of fluid temperature becomes excessive at the furnace outlet, with the result that excessive stress acts on the furnace wall. More specifically, there are produced portions in which a dryness differs due to ununiformity in heat absorption. In this case, the portion having a high dryness increases in volumetric flow rate but decreases in weight flow rate, which in turn further increases the dryness. Whereas in the portion having a low dryness, the dryness reversely further decreases. the imbalance increasingly grows.
  • variable-pressure once-through boiler furnace evaporating tube the adjacent evaporating tubes communicate with each other via headers disposed outwardly of a furnace wall surface.
  • variable-pressure once-through boiler furnace evaporating tube the adjacent evaporating tubes communicate with each other via cross branch tubes disposed inwardly of the furnace wall surface.
  • the adjacent perpendicular furnace wall tubes communicate with each other at the middle portions of the upper and lower headers.
  • the internal fluids flowing in from the lower part of the furnace are mixed with each other at the communicating portions and made uniform in the upper part of the furnace.
  • FIG. 1 is a perspective view showing a first embodiment of the present invention.
  • FIG. 2 is a view taken in an arrowed direction II of FIG. 1, illustrating an interior of a boiler furnace.
  • FIG. 3 is an entire perspective view showing one example of a boiler to which the present invention is applied.
  • an upper front wall header 4 of the front part Disposed rectangularly at the upper end of the boiler furnace in FIG. 3 are an upper front wall header 4 of the front part, an upper rear wall header 5 of the rear part and upper side wall headers 6, 6 on both sides.
  • a lower collecting header 2 is disposed to extend on both sides of the lowermost part at the lower end thereof, and a plurality of furnace wall tubes 1 extend forwards and backwards therefrom to shape a furnace bottom.
  • the wall tubes are thereafter connected to constitute front and rear walls.
  • Lower wall headers 3, 3 are disposed on both sides.
  • the plurality of furnace wall tubes 1 are so connected thereto as to be directed upwards.
  • the upper ends of the vertical furnace wall tubes 1 are connected to the upper front wall header 4, the upper rear wall header 5 and the upper side wall headers 6, 6, thus constituting the furnace.
  • the plurality of furnace wall tubes 1 constituting the furnace wall are alternately bent outwards along the horizontal planes of upper and lower two portions at the middle part (a part indicated by the symbol A in FIG. 3) between the upper headers 4, 5, 6, 6 and the lower headers 2, 3, 3.
  • the furnace wall tubes 1 are connected to a middle header 7 disposed outwardly of the furnace wall surface.
  • the adjacent furnace wall tubes 1 communicate with each other via this middle header 7. Even when the dryness becomes ununiform at the lower part of the furnace, the ununiform fluids are mixed with each other, whereby these fluids are made uniform at the upper part of the furnace.
  • the furnace wall tubes 1 are alternately bent along the horizontal planes of the upper and lower two portions. If these tubes are bent along the horizontal plane of one portion, the same effects can be also obtained.
  • FIGS. 4 and 5 show a second embodiment of this invention.
  • FIG. 4 is a vertical sectional view depicting the furnace wall at the part A of FIG. 3.
  • FIG. 5 is a horizontal sectional view illustrating the furnace wall of the part B of FIG. 3.
  • the adjacent wall tubes 1 communicate with each other via cross branch tubes 8a.
  • the cross branch tubes 8a are connected via elbows 9a to the respective wall surfaces (front surface, rear surface and side surfaces) of the furnace.
  • the internal fluids are thereby movable.
  • This embodiment also exhibits the same operating effects as those of the first embodiment.
  • FIG. 5 shows an example where the furnace wall tubes 1 are provided at the corner part of the furnace. If no furnace wall tube exists at the corner part, the respective wall surfaces may be connected by using elbows 9b shown in FIG. 7.
  • the uniformity can be made effective by adopting the first embodiment which uses mainly the middle headers.
  • a furnace capable of setting the uniformity to a small degree it is effective to employ the structurally simple cross branch tubes of the second embodiment.
  • the present invention is effective especially in coal burning and oil burning.
  • the present invention is effective in such a design that the ununiform degree of the heat absorption of the furnace is particularly large, or an overheating degree at the furnace outlet has to be set high.
  • all the adjacent tubes are horizontally connected to each other in the middle of the plurality of furnace wall tubes of the vertical tube type furnace variable-pressure operating boiler.
  • the internal fluids are movable between the neighboring tubes. It is therefore possible to minimize the imbalance of the fluid temperatures which is caused at the furnace outlet. This eliminates the possibility that the excessive stress acts on the furnace wall.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
EP91109486A 1990-06-18 1991-06-10 Ensemble de tubes d'évaporation d'un foyer d'une chaudière à passage unique sous pression variable Withdrawn EP0462486A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP15771590A JPH0448105A (ja) 1990-06-18 1990-06-18 変圧貫流ボイラ火炉蒸発管
JP157715/90 1990-06-18

Publications (1)

Publication Number Publication Date
EP0462486A1 true EP0462486A1 (fr) 1991-12-27

Family

ID=15655797

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91109486A Withdrawn EP0462486A1 (fr) 1990-06-18 1991-06-10 Ensemble de tubes d'évaporation d'un foyer d'une chaudière à passage unique sous pression variable

Country Status (2)

Country Link
EP (1) EP0462486A1 (fr)
JP (1) JPH0448105A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993013356A1 (fr) * 1991-12-20 1993-07-08 Siemens Aktiengesellschaft Generateur de vapeur en continu alimente par matiere fossile

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE682498A (fr) * 1965-06-15 1966-12-14
US3308792A (en) * 1965-08-26 1967-03-14 Combustion Eng Fluid heater support
GB1152340A (en) * 1965-12-13 1969-05-14 Combustion Eng Forced-Through-Flow Type Vapor Generator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE682498A (fr) * 1965-06-15 1966-12-14
US3308792A (en) * 1965-08-26 1967-03-14 Combustion Eng Fluid heater support
GB1152340A (en) * 1965-12-13 1969-05-14 Combustion Eng Forced-Through-Flow Type Vapor Generator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993013356A1 (fr) * 1991-12-20 1993-07-08 Siemens Aktiengesellschaft Generateur de vapeur en continu alimente par matiere fossile
US5735236A (en) * 1991-12-20 1998-04-07 Siemens Aktiengesellschaft Fossil fuel-fired once-through flow stream generator

Also Published As

Publication number Publication date
JPH0448105A (ja) 1992-02-18

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