US3662716A - Furnance enclosure for natural circulation generator - Google Patents

Furnance enclosure for natural circulation generator Download PDF

Info

Publication number
US3662716A
US3662716A US97700A US3662716DA US3662716A US 3662716 A US3662716 A US 3662716A US 97700 A US97700 A US 97700A US 3662716D A US3662716D A US 3662716DA US 3662716 A US3662716 A US 3662716A
Authority
US
United States
Prior art keywords
enclosure
furnace
generator
tubes
diameter
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
US97700A
Other languages
English (en)
Inventor
William D Stevens
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.)
Foster Wheeler Inc
Original Assignee
Foster Wheeler Inc
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 Foster Wheeler Inc filed Critical Foster Wheeler Inc
Application granted granted Critical
Publication of US3662716A publication Critical patent/US3662716A/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
    • F22B21/00—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically
    • F22B21/34—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically built-up from water tubes grouped in panel form surrounding the combustion chamber, i.e. radiation boilers
    • F22B21/341—Vertical radiation boilers with combustion in the lower part
    • F22B21/343—Vertical radiation boilers with combustion in the lower part the vertical radiation combustion chamber being connected at its upper part to a sidewards convection chamber
    • F22B21/345—Vertical radiation boilers with combustion in the lower part the vertical radiation combustion chamber being connected at its upper part to a sidewards convection chamber with a tube bundle between an upper and a lower drum in the convection pass
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B21/00—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically
    • F22B21/34—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically built-up from water tubes grouped in panel form surrounding the combustion chamber, i.e. radiation boilers
    • F22B21/341—Vertical radiation boilers with combustion in the lower part
    • F22B21/343—Vertical radiation boilers with combustion in the lower part the vertical radiation combustion chamber being connected at its upper part to a sidewards convection chamber

Definitions

  • ABSTRACT A natural circulation generator having a rectangular furnace enclosure.
  • a plurality of parallel, upright, finned tubes welded together along their lengths make up the walls of the enclosure. Burners are provided in the front wall of the enclosure, in the lower portion thereof, providing a heat input to the finned tubes.
  • the tubes have a first diameter in the lower portion of the furnace, and a second greater diameter in the upper portion of the furnace. The increased tube diameter in the upper portion of the furnace gives a higher circulation ratio in the generator, and in addition provides more heat absorption surface area which increases the throughput steam flow per hour-foot of furnace periphery. This enables construction of a natural circulation unit having increased capacity.
  • the present invention relates to natural circulation generators, and particularly to an improved furnace arrangement which enables the construction of natural circulation generators of higher capacity.
  • Natural circulation generators heretofore have been limited in size primarily because of the head available for circulation.
  • the head or motive force in a natural circulation unit is dependent upon the difference in density between the flow in the downflow circuit and that in the upflow circuitry, minus losses from friction, shock, turbulence and other factors, which losses increase with increased capacity or size, Also, relatively high pressures are employed today in natural circulation units, further causing a reduction in the head available for circulation.
  • circulation ratio or ratio of weight rate of water fed to the steam generator tubes divided by the weight rate of steam generated.
  • Another object of the present invention is to provide a natural circulation generator of greater capacity in which the likelihood of failure of tubes in the furnace wall circuitry is reduced.
  • Still another object of the present invention is to provide a natural circulation generator having a high circulation ratio in which the throughput steam flow per foot of periphery in the furnace walls of the generator is increased.
  • a still further object of the present invention is to provide a large capacity natural circulation generator in which conventional tube materials can be employed.
  • the invention comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexeddrawingsetting forth in detail a certain illustrative embodiment of the invention, this being indicative, however, of but only one of the various ways in which the principles of the invention may be employed.
  • FIG. 1 is a section, elevation view illustrating a natural circulation generator in accordance with the concepts of the invention
  • FIG. 2 is an enlarged, perspective view of a portion of the furnace enclosure tube wall of the generator of FIG. 1;
  • FIG. 3 is an enlarged partial elevation view of a tube wall of the generator of FIG. 1 taken in zone B-B of the generator furnace enclosure.
  • the vapor generator in accordance with the present invention is broadly indicated with the letter A, and comprises a vertically extending rectangular shaped radiant furnace area B having an upper gas exit C, and a convection area D which leads downwardly from the gas exit.
  • a burner zone E occupies the furnace area of the generator immediately above hopper F. The flow of hot gases is upwardly in the furnace area from the burner zone, through the convection areas of the generator to the generator outlet G, and from there to a conventional air heater H for heat exchange between hot gases and incoming air for the burners.
  • the present invention is concerned primarily with the construction of the furnace portion B of the generator.
  • the vapor generator furnace comprises an upright, rectangular enclosure 12 defined by front and rear walls l4, 16.
  • Side walls 18 extend between the front and rear walls, the entire enclosure leading vertically from the bottom hopper F to an inclined roof 22.
  • Beneath the roof 22, the rear wall is bent inwardly and thenrearwardly to provide a reverse arch 24, above which the wall is branched at the furnace exit C into parallel but spaced apart, open screen tube panels 26, 28 which permit the flow of gas from the furnace area of the generator to the generator convection area.
  • the generator comprises a generally, rectangular enclosure 30 separated into two gas passes 32, 34 by a division wall 36.
  • the rearmost of the two gas passes houses the generator reheater section 38, the other of the gas passes containing superheater and economizer sections 40, 42, respectively.
  • the upper zone 44 of the furnace above the burner zone E, contains a plurality of J-shaped division wall panels 46 in the front of the furnace area, and a pendant finishing superheating section 48 above the arch 24 in the rear wall of the generator.
  • the pendant finishing superheater is positioned immediately in front of the screen panels 26, 28 leading to the convection area of the generator.
  • the flow of the fluid being heated in the generator is from the economizer 42 into the lower inlet headers 50 for the radiantly heated walls 14, 16 and 18 of the generator enclosure.
  • the flow in these walls is upwardly in generally parallel tubes of the walls into risers 52 at the top of the generator and from there into the steam and water drums 54, 56. Liquid separated from the flow in the drums is recycled by downcomers 58 to the lower inlet headers of the enclosure, by natural circulation.
  • Vapor separated from the flow in the steam and water drums is transmitted by conduits 60 into an inlet header62 for the downwardly inclined roof 22 of the generator.
  • a header 64 divides the fluid for flow into the walls of the convection enclosure 30 of the generator and into the division wall 36 of the convection area. These walls terminated in a lower header 66 at the bottom of the convection area, from which the flow is transmitted into the bank 40 of the primary superheating tubes. From there via additional headers and conduits, the flow is into the division wall panels 46, and pendant finishing superheating sections 48 in that order.
  • a membrane-type wall construction illustrated in detail in FIG. 2 is employed substantially throughout all of the furnace walls of the generator, except for the screen tube panels 26 and 28 at the gas exit C, and except where the walls are penetrated, forinstance, by the burners and division wall panels.
  • This membrane-type wall construction is obtained by welding together a plurality of finned tubes 68 along their lengths so that the enclosure is substantially gas-tight.
  • the furnace enclosure is divided into higher and lower temperature tube panel sections B and B", the higher temperature section B being roughly coextensive with the enclosure burner zone E, and extending from near the bottom of the furnace to an elevation above the burners 70; the lower temperature sections B" constituting the remainder of the furnace enclosure up to the roof and being roughly coextensive with the upper zone 44 of the enclosure.
  • the tube diameters are increased in the panel sections in a transition area 72 between the burner and lower temperature zones, being smaller in diameter in the burner zone and larger in diameter in the upper zone.
  • the use of large diameter tubing in the upper zone has the advantage of increasing the surface area for heat absorption, for a given furnace periphery, and to thereby obtain a relatively high throughput steam flow per foot of periphery, in the order of 20,000 lbs. per hour-foot in the unit described. It also reduces friction and other losses to insure a high circulation ratio in the generator, sufficiently high so that the least favorable circuit receives an adequate water supply.
  • Positioning the division wall and finishing superheater surfaces in the upper furnace has the advantage that it reduces gas temperature at the gas exit to within design limits. In this respect, it permits limiting the amount of surface area in the furnace perimeter to that necessary to attain the required circulation ratio. Location of these surfaces in a high heat intensity zone also facilitates control of superheat temperatures.
  • a natural circulation generator of increased capacity comprising a rectangular furnace enclosure; a plurality of parallel upright tubes welded together along 5 their lengths forming the walls of the enclosure;
  • the tube sizes in the lower portion of the enclosure being of one diameter, those in the upper portion of the furnace, above the burners, being of a larger diameter to provide an increased throughput steam flow per foot of furnace periphery, whereby the friction and shock losses are reduced in said upper portion and a higher circulation ratio is achieved in the entire circuit.
  • the generator of claim 4 including a convection zone connected with the furnace enclosure gas exit means, the convection zone housing reheater, superheater and economizer tube surface.
  • furnace enclosure comprises front, rear and side walls, the tubes of the rear wall immediately below the gas exit means being bent inwardly to the furnace and then rearwardly to form a reverse arch penetrating into the furnace for deflection of hot gases across said division wall means.
  • said division wall means comprises .l-shaped panels of tubes having ends penetrating the front wall of the generator and the roof of the generator, the elevation of penetration of the front wall being above the area of transition in the enclosure wall tubes from the smaller diameter tubes to the larger diameter tubes.
  • a natural circulation generator of increased capacity comprising a rectangular furnace enclosure
  • the tube sizes in the lower portion of the enclosure being of one diameter, those in the upper portion of the enclosure being of a larger diameter;
  • the tube diameter in the lower portion of the enclosure being sufficiently small to permit the use of plain carbon steel tubing
  • the tube diameter in the upper portion of the enclosure being sufficiently larger in diameter to obtain that circulation ratio and throughput steam flow per hour-foot of furnace periphery required;

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Tunnel Furnaces (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
US97700A 1970-12-14 1970-12-14 Furnance enclosure for natural circulation generator Expired - Lifetime US3662716A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US9770070A 1970-12-14 1970-12-14

Publications (1)

Publication Number Publication Date
US3662716A true US3662716A (en) 1972-05-16

Family

ID=22264714

Family Applications (1)

Application Number Title Priority Date Filing Date
US97700A Expired - Lifetime US3662716A (en) 1970-12-14 1970-12-14 Furnance enclosure for natural circulation generator

Country Status (8)

Country Link
US (1) US3662716A (es)
JP (1) JPS5632521B1 (es)
AU (1) AU461157B2 (es)
CA (1) CA928177A (es)
ES (1) ES397904A1 (es)
FR (1) FR2118589A5 (es)
GB (1) GB1367479A (es)
NL (1) NL7117120A (es)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909501A (en) * 1973-05-22 1975-09-30 Int Standard Electric Corp Hollow conductor power cable
US5049240A (en) * 1989-02-10 1991-09-17 Shell Oil Company Vaccum distillation system
US5934227A (en) * 1995-04-05 1999-08-10 The Babcock & Wilcox Company Variable pressure once-through steam generator upper furnace having non-split flow circuitry
US20070144456A1 (en) * 2003-11-19 2007-06-28 Rudolf Kral Continuous steam generator
US20110132281A1 (en) * 2008-12-03 2011-06-09 Mitsubishi Heavy Industries, Ltd. Boiler structure
US20200200047A1 (en) * 2016-06-23 2020-06-25 Nanyang Technological University Waste-to-energy plant

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1223108A (en) * 1914-04-16 1917-04-17 Ets Delaunay Belleville Sa Belleville-boiler elements with tubes of increasing diameter.
US1842235A (en) * 1929-06-21 1932-01-19 Superheater Co Ltd Water tube boiler
US2987052A (en) * 1958-09-29 1961-06-06 Comb Engineers Inc Wall construction for pressurized furnace
US3060908A (en) * 1958-05-13 1962-10-30 Babcock & Wilcox Co Fluid heating unit

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3162179A (en) * 1962-12-05 1964-12-22 Gilbert Associates Fluid circulation system for a oncethrough type steam generator

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1223108A (en) * 1914-04-16 1917-04-17 Ets Delaunay Belleville Sa Belleville-boiler elements with tubes of increasing diameter.
US1842235A (en) * 1929-06-21 1932-01-19 Superheater Co Ltd Water tube boiler
US3060908A (en) * 1958-05-13 1962-10-30 Babcock & Wilcox Co Fluid heating unit
US2987052A (en) * 1958-09-29 1961-06-06 Comb Engineers Inc Wall construction for pressurized furnace

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909501A (en) * 1973-05-22 1975-09-30 Int Standard Electric Corp Hollow conductor power cable
US5049240A (en) * 1989-02-10 1991-09-17 Shell Oil Company Vaccum distillation system
US5934227A (en) * 1995-04-05 1999-08-10 The Babcock & Wilcox Company Variable pressure once-through steam generator upper furnace having non-split flow circuitry
US20070144456A1 (en) * 2003-11-19 2007-06-28 Rudolf Kral Continuous steam generator
US7516719B2 (en) * 2003-11-19 2009-04-14 Siemens Aktiengesellschaft Continuous steam generator
US20110132281A1 (en) * 2008-12-03 2011-06-09 Mitsubishi Heavy Industries, Ltd. Boiler structure
US9134021B2 (en) * 2008-12-03 2015-09-15 Mitsubishi Heavy Industries, Ltd. Boiler structure
US20200200047A1 (en) * 2016-06-23 2020-06-25 Nanyang Technological University Waste-to-energy plant
US10989077B2 (en) * 2016-06-23 2021-04-27 Nanyang Technological University Waste-to-energy plant

Also Published As

Publication number Publication date
CA928177A (en) 1973-06-12
AU3677371A (en) 1973-06-14
JPS5632521B1 (es) 1981-07-28
ES397904A1 (es) 1975-05-01
FR2118589A5 (es) 1972-07-28
AU461157B2 (en) 1975-05-15
NL7117120A (es) 1972-06-16
GB1367479A (en) 1974-09-18

Similar Documents

Publication Publication Date Title
US3267913A (en) Apparatus and method for supporting tubes
US3030937A (en) Furnace wall and support
US2730080A (en) Vapor generating installation, including a cyclone furnace
GB1114441A (en) Multiple pass arrangements for once-through steam generators
US3662716A (en) Furnance enclosure for natural circulation generator
US2213185A (en) Combined radiant and convection superheater
GB1273244A (en) Improvements in or relating to heat exchangers
US2834324A (en) Vapor generator with high temperature pendent superheater platens
US2293040A (en) Steam generator
US2681641A (en) Vapor generating and superheating installation
US3343523A (en) Vapor generator
US3060908A (en) Fluid heating unit
US2244451A (en) Water walls and the like
US3888213A (en) Boilers
US3280800A (en) Vapor generator having boiler bank supported by downcomers
US2332534A (en) Steam generator
US2976857A (en) Vapor generator with panel superheating means
US2114224A (en) Steam boiler
US1930688A (en) Boiler
US2123860A (en) Steam generator
GB1299061A (en) Once through vapour generator with division wall
US3754533A (en) Tube support system
US2299732A (en) Steam generator
US2207247A (en) Steam generator
US2725042A (en) Fluid cooled tubular panels