US3816063A - Process for heating industrial furnaces - Google Patents

Process for heating industrial furnaces Download PDF

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Publication number
US3816063A
US3816063A US00317121A US31712172A US3816063A US 3816063 A US3816063 A US 3816063A US 00317121 A US00317121 A US 00317121A US 31712172 A US31712172 A US 31712172A US 3816063 A US3816063 A US 3816063A
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United States
Prior art keywords
air
fuel oil
set forth
furnace
percent
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Expired - Lifetime
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US00317121A
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English (en)
Inventor
M Hicguet
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RECH SCHENTIFIQUES ET MINIERES
SOC ETUDES ET DE RECHERCHES SCHENTIFIQUES ET MINIERES FR
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RECH SCHENTIFIQUES ET MINIERES
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C99/00—Subject-matter not provided for in other groups of this subclass
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2700/00—Special arrangements for combustion apparatus using fluent fuel
    • F23C2700/02—Combustion apparatus using liquid fuel
    • F23C2700/026—Combustion apparatus using liquid fuel with pre-vaporising means

Definitions

  • the invention relates to a process and apparatus for heating industrial furnaces wherein liquid fuel oil at a temperature of 250C. to 500C. and a pressure of 8 to bars is mixed with a quantity of primary air amounting to 25 to percent of the amount required for complete combustion, and this mixture is subsequently mixed with a quantity of secondary air amounting to 15 to 35 percent of the amount required for complete combustion.
  • the object of the present invention is especially to make the production of fuel oil vapors, for feeding furnaces, easier and more economical.
  • a process for the heating 'of industrial furnaces by means of vapors produced by expansion of hot liquid fuel oil under pressure comprising taking a starting material consisting of liquid fuel oil at a temperature of 250C. to 500C, under a pressure of the order of 8 to 50 bars, injecting the fuel oil into a pre-combustion and heating chamber in free communication with the interior of a furnace in such a manner that it expands and vaporizes in said chamber, introducing primary air into this same chamber in the immediate vicinity of the fuel inlet, introducing secondary air at a distance from the fuel.
  • the rate of introduction of air in each case relative to the amount of air required for completecombustion of the fuel oil being 25 to 60 percent in the case of the primary air and to 35 percent in the case of the secondary air.
  • the primary air introduced in the vicinity of the fuel inlet causes partial combustion of the fuel, with conver-v sion of a large part of the carbon contained in the fuel oil into carbon monoxide, and the secondary air causes the practically complete conversion 'of the remainder of this carbon into carbon monoxide while moderating the temperature of the walls of the chamber for precombustion and heating of the fuel vapors, in particular near the burner or burners through which the fuel oil is injected.
  • a further charging of secondary air introduced may be fed in at a later stage in the combustion cycle.
  • the production of fuel oil vapor from hot liquid under pressure differs from the known mechanical spraying or atomizing, in which a liquid fuel which is cold or at a slightly elevated temperature is converted into small droplets which thereafter vaporize more or less imperfectly to producea carbonaceous deposit.
  • the pressure range of about 8 to 50 bars is so chosen that regardless of the viscosity of the fuel oil (whether it is light fuel oil or heavy fuel oil), the fuel oil remains liquid at the temperature employed.
  • the air can be introduced hot throughout, preferably at a temperature of at least 250C. or can only be introduced hot during the light up phase of the boiler operating cycle and thereafter be replaced by cold air. It is furthermore possible, according to the present invention to introduce as hot air, both the primary air in the vicinity of the fuel inlet and secondary air at a distance from this inlet.
  • furnaces such as furnaces for roasting chalk, dolomite or magnesia, and blast furnaces and boilers.
  • air at a very high temperature generally of the order of 800C. to l,350C. is available; this can be used as it is, if necessary introducing cold a small portion of the primary air, so as to moderate the temperature of the walls of the fuel oil injection nozzles.
  • apparatus for carrying out the above process comprising a space into which the fuel oil is to be injected, and a nozzle which comprises a central device terminating in a calibrated outlet orifice for introducing the fuel into said space,
  • the device for introducing the fuel may comprise a hollow blowpipe which is detachable so as to be interchangeable with other similar blowpipes, and has an intemal chamber which opens into a calibrated orifice or jet which regulates the flow rate of the fuel, and at the outlet of which orifice the fuel expands.
  • FIG. 1 is a transverse section of a vertical furnace equipped for carrying out the method of the invention
  • FIG. 2 represents a detail on a larger scale
  • FIG. 3 relates to a variant of FIG. 2 and FIG. 4 to a variant of a part of FIG. 1;
  • FIG. 5 is a schematic vertical section of a blast furnace equipped for carrying out the method of the invention.
  • FIG. 6 is a section along VI-VI of FIG. 5.
  • FIG. 7 shows schematically on a large scale a detail of the fuel oil nozzleof FIG. 5;
  • FIG. 8 similar to FIG. 7, relates to an alternative embodiment of a fuel oil nozzle
  • FIG. 9 is similar to FIG. 1 and shows schematically an installation for heating and for distributing the fuel between the various nozzles.
  • FIGS. 1 and 2 show a vertical furnace such as is used, for example, for roasting dolomite.
  • the furnace comprises an internal tubular portion made of bricks 1, consisting of a basic material such as magnesia or dolomite, an intermediate layer 2 also of basic material, and an external layer 3 which is heat insulating and made of acid bricks, the whole beingencased in a sheet metal jacket 4.
  • Radially extending pre-combustion and heating chambers 9 for the fuel vapors are defined in the wall of the furnace byplanes which are themselves radial to the axis of this furnace. In the example they number eight, but there can be fewer for example four, or more for example 12 or more, depending on the diameter of the furnace.
  • the nozzle 11 comprises a blowpipe consisting of an axial tube 11a which at its outward end carries ajet consisting of a plug 11b in which a calibrated outlet orifice He is machined; in turn, the blowpipe is placed in a tube 11d serving as a jacket; the annular space 11f between the jacket 11d and a tube 11:: of greater diameter serves to introduce primary air, which is preferably caused to rotate.
  • the liquid fuel is fed in hot (250C. to 500C.) and under pressure (8 to 50 bars) through the tube 1 la and is ejected through the orifice 110.
  • the primary air preferably at a temperature of at least 250 C., is introduced through the space 11f contained between the jacket 11d and the tube llle so as to issue in the immediate vicinity of the point of injection of the fuel.
  • the entire nozzle 11 can be carried by a fitting 11g attached to the walls of the antechamber 9.
  • the fuel oil vapor produced at the outlet of the tube 1 la burns partially or completely in the chamber 9 and issues from the latter at its inner end, while entering the internal space of the furnace.
  • the blowpipe 11a, 11b is preferably detachable so that it can be cleaned, or if necessary replaced by another the plug of which has a calibrated orifice of different diameter so as to change the fuel flow rate or be appropriate for a fuel having a different viscosity.
  • the nozzle consists principally of a central tube 150 which carries internally at its end a plug15b having a calibrated orifice 15c, and which is mounted in a tube 15d of greater diameter.
  • the fuel oil is introduced through the tube 150 and the primary air is introduced through the annular space 15e between the two tubes.
  • the chamber 16 instead of being in the shape of a truncated pyramid as in FIG. 1 opens into the inner space of the furnace through an air vent of restricted cross-section machined in the innerrow of bricks.
  • the side walls 17a and 17b of the antechamber and those 18a and 18b of the air vent are connected to one another by incurved walls 19a and 1% which thus form a zone of turbulence for the fuel oil vapors and for the primary air coming from the nozzle 20.
  • the blast furnace represented schematically in FIGS. 5 and 6 is provided, in its so-called working portion,
  • a fuel nozzle 24, shown in detail in FIG. 7, is mounted in each blow nozzle.
  • the burner comprises an internal tube 24a which carries at its end a plug 24b having a calibrated orifice 240.
  • the nozzle 24 has an annular chamber 24d defined by an internal tube 25e and an external tube 25f. The fuel nozzle 24 is held in an axial position within the blow nozzle 21 by means of a fitting 26.
  • the nozzle 24, instead of being mounted axially in the blowpipe 21, is mounted obliquely relative thereto with its axis in a plane which passes through the axis of the blow nozzle and which is either vertical as shown, or if necessary is inclined horizontal.
  • the plugs or jets such as 11b, 15b and 24b can be produced in a known manner so as to impart a vortical movement to the issuing liquid fuel.
  • the furnace equipment is similar to that of FIG. 1 and all that will be described here is that which concerns feeding the nozzles 27 with a liquid fuel from a tank 28.
  • the tank 28, or the pipeline 29 connected thereto. is equipped with a heating device 30.
  • the pipeline 29 is connected to a toroidal manifold 31 and includes a pump 32.
  • at least one heating device is combined with this pipeline.
  • Three such heating devices have been shown in the drawing, the first 33 being in the form of a heating resistance, the second 34 being in the form of a coil forming part of a circuit passing a source 35 of hot fluid (gas or vapors, fumes or thermal fluid), and the third 36 being in the form of a resistance which encloses not only the tube 29 but also the manifold 31.
  • a process for heating industrial furnaces with vapors produced by expansion of hot liquid fuel oil under pressure comprising: providing liquid fuel oil at a temperature of 250 to 500C, under a pressure of 8 to 50 bars, injecting said heated and pressurized fuel oil into a precombustion and heating chamber which is in free communication with the interior of a furnace, thereby expanding and vaporizing said fuel oil in said chamber, introducing air into saidchamber in the immediate vicinity of the fuel inlet thereto and introducing the resulting mixture into the interior of the furnace.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion Of Fluid Fuel (AREA)
  • Air Supply (AREA)
US00317121A 1971-12-23 1972-12-21 Process for heating industrial furnaces Expired - Lifetime US3816063A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7146373A FR2165258A5 (es) 1971-12-23 1971-12-23

Publications (1)

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US3816063A true US3816063A (en) 1974-06-11

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ID=9087961

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US00317121A Expired - Lifetime US3816063A (en) 1971-12-23 1972-12-21 Process for heating industrial furnaces

Country Status (15)

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US (1) US3816063A (es)
JP (1) JPS4872738A (es)
AR (1) AR209060A1 (es)
BE (1) BE793215A (es)
BR (1) BR7208935D0 (es)
CA (1) CA957936A (es)
CH (1) CH565355A5 (es)
DE (1) DE2262771A1 (es)
ES (1) ES409778A1 (es)
FR (1) FR2165258A5 (es)
GB (1) GB1405646A (es)
IT (1) IT974715B (es)
LU (1) LU66735A1 (es)
NL (1) NL7217539A (es)
TR (1) TR17655A (es)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4060376A (en) * 1974-12-11 1977-11-29 Energiagazdalkodasi Intezet Method of firing and furnace therefor
US4060378A (en) * 1974-12-11 1977-11-29 Energiagazdalkodasi Intezet Method of firing and furnace therefor
US4072502A (en) * 1973-03-26 1978-02-07 Skf Industrial Trading And Development Co. B.V. Method apparatus for increasing blast gas temperature in a shaft furnace

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3091446A (en) * 1962-02-19 1963-05-28 Union Carbide Corp Method for the heating of industrial furnaces
US3400921A (en) * 1965-10-06 1968-09-10 Babcock & Wilcox Co Fuel burner
US3582053A (en) * 1968-02-28 1971-06-01 Centre Nat Rech Metall Method and apparatus for injecting liquid fuel into a shaft furnace

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3091446A (en) * 1962-02-19 1963-05-28 Union Carbide Corp Method for the heating of industrial furnaces
US3400921A (en) * 1965-10-06 1968-09-10 Babcock & Wilcox Co Fuel burner
US3582053A (en) * 1968-02-28 1971-06-01 Centre Nat Rech Metall Method and apparatus for injecting liquid fuel into a shaft furnace

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4072502A (en) * 1973-03-26 1978-02-07 Skf Industrial Trading And Development Co. B.V. Method apparatus for increasing blast gas temperature in a shaft furnace
US4060376A (en) * 1974-12-11 1977-11-29 Energiagazdalkodasi Intezet Method of firing and furnace therefor
US4060378A (en) * 1974-12-11 1977-11-29 Energiagazdalkodasi Intezet Method of firing and furnace therefor

Also Published As

Publication number Publication date
IT974715B (it) 1974-07-10
TR17655A (tr) 1975-07-23
GB1405646A (en) 1975-09-10
JPS4872738A (es) 1973-10-01
ES409778A1 (es) 1976-01-01
BR7208935D0 (pt) 1973-09-20
NL7217539A (es) 1973-06-26
AR209060A1 (es) 1977-03-31
DE2262771A1 (de) 1973-07-05
BE793215A (fr) 1973-06-22
FR2165258A5 (es) 1973-08-03
CA957936A (en) 1974-11-19
LU66735A1 (es) 1973-02-22
CH565355A5 (es) 1975-08-15

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