US3788622A - Furnace - Google Patents

Furnace Download PDF

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Publication number
US3788622A
US3788622A US00310719A US3788622DA US3788622A US 3788622 A US3788622 A US 3788622A US 00310719 A US00310719 A US 00310719A US 3788622D A US3788622D A US 3788622DA US 3788622 A US3788622 A US 3788622A
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United States
Prior art keywords
furnace
wall
space
elements
compressible
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Expired - Lifetime
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US00310719A
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English (en)
Inventor
Laar J Van
J Felthuis
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Hoogovens Ijmuiden BV
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Hoogovens Ijmuiden BV
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B7/00—Blast furnaces
    • C21B7/10—Cooling; Devices therefor
    • C21B7/106—Cooling of the furnace bottom

Definitions

  • ABSTRACT A furnace provided with a wall and a refractory inner masonry structure, between which there is a space, there being compressible elements from a material of high heat conductivity arranged in contact with the walls of said space, for improving heat discharge from the interior of the furnace.
  • the said space may be filled with a ramming mix or tamping mixture.
  • the elements are preferably copper pipes.
  • said space will be annular around the furnace and the elements are provided at regular intervals and compressible in a radial direction with respect to the furnace.
  • This invention relates to a furnace provided with a wall and a refractory inner lining of bricks, between which wall and lining there is a narrow space.
  • Furnaces in particular blast furnaces, are often provided with exterior cooling means for discharging heat flow from the refractory brick work, which heat flow particularly for a large furnace will be considerable.
  • a small space is left open intentionally when making the masonry, in order to be able to take up thermal expansions of the masonry.
  • This space is usually filled with a socalled ramming mix or tamping mixture, usually consisting of a mixture of granular graphite or carbon and tar.
  • a ramming mix is more or less porous and thus compressible.
  • the disadvantage of such a mix is, however, the low heat conductivity thereof, which in several cases is even lower than the conductivity of the masonry. This results in a loss of heat discharge to the exterior, which in the long run is not favourable for the masonry. If the ramming mix has to take up the fullthermal expansion of the masonry, the necessary thickness of the layer of ramming mix increases with the diameter of the furnace, and this will result in an increase of the heat insulating capacity of the layer.
  • the refractory inner masonry and the wall are according to the invention brought in heat conducting contact by the presence of compressible elements from thermally good conductive material provided at regular intervals and compressible in a radial direction.
  • Such elements may have different possible shapes.
  • the most simple and least expensive possibility is the use of copper pipes as such elements. If the faces bordering the said space have a mutually somewhat converging shape and if the largest distance between these surfaces is at most equal to the outer diameter of the pipes there will with certainty be obtained a good heat conductive contact between both surfaces after arranging the pipes.
  • the wall as indicated willbe an outer wall or mantle of the furnace, but need not be the outermost wall, as it may be the inner wall of a double walled cooling space, through which a cooling liquid is passed.
  • FIG. 1 shows an axial, vertical section through a blast furnace bottom with part of the upstanding walls, in which the invention is applied.
  • FIG. 2 shows a horizontal section through part of the bottom along the line IIII in FIG. 1 on an enlarged scale.
  • reference numeral 1 indicates a steel mantle or outer wall around a refractory bottom structure for the furnace. This mantle or outer wall is connected to a steel bottom plate 2 supported on a structure of steel beams not shown in the drawings. As stated, the outer wall 1 may be the inner wall of a double-walled space for a cooling liquid.
  • the bottom In a blast furnace the bottom is subjected to continuous heavy thermal loads as a result of the quantity of liquid iron above the bottom, the temperatures in the vicinity of the tap hole 8 being about 1,400C 1,500C.
  • the bottom should be resistant to such high temperatures, but also it has the function to support a large part of the blast furnace structure and the contents thereof. In order to be able to fulfil the requirements for the supporting function it is necessary that those parts of the bottom which substantially support the structure have rather low temperatures.
  • a complication in blast furnace bottoms consists in that they are gradually attacked by the liquid iron.
  • This liquid iron has the tendency for most of the refractory materials in use to penetrate into the bottom to a depth where the temperature of the bottom is about equal to the solidification temperature of iron, which is about 1,130C.
  • the zone above this temperature limit will gradually be attacked and worn out, whereby the said temperature limit is displaced downwardly, until an equilibirum condition has been attained.
  • the so-called salamander thereis a temperature gradient in the vertical direction.
  • the salamander will be filled from top to bottom with liquid iron and possibly in part with solid iron, and often in part also with a coke matrix or skeleton.
  • the temperature of the graphite layer will be decreased to below the solidification temperature of the iron, which avoids that the salamander can penetrate downwardly into the graphite layer.
  • the lower layer consisting of less conductive material, restricts the heat flow to and through the steel bottom plate. The remainder of the heat will thereby be transferred to the periphery of the graphite layer and will thus be discharged through the steel mantle or outer wall. With the aid of the liquid cooling above indicated by means not shown, the temperature thereof is kept sufficiently low.
  • the bottom proper is built up of four layers indicated by 4, 5, 6 and 7 in the drawing.
  • the upper layer 4 with a thickness of about 60 cm consists of semi-graphite.
  • the heat conduction coefficient A of such semigraphite is about 20 kcal/m/h/C.
  • Layer 5 has a thickness of about 60 cm and consists of blocks of graphite with a coefficient of about 90 kcal/m/h/C, which have been carefully finished as to the shape and accuracy of their outer walls.
  • Layer 6 also consists of blocks of graphite laid in directions perpendicular to the direction in which the blocks in layer 5 are oriented. Both layers are provided with dilatation joints in order to be able to take up the thermal expansions of the graphite in operating conditions.
  • Layer 7 has a thickness of about 60 cm and consists of carbon bricks with a coefficient A of about 4 kcal/m/h/C. The said coefficient values are given for operating conditions and not for normal temperatures.
  • the furnace diameter in the hearth may be about 13 in.
  • the outer mantle or wall 1 is cooled down to about 60C.
  • a fan shown of e.g., a power of 100 horse powers is used to blow air along the steel bottom plate 2 to keep it cooled to a temperature below 100C.
  • the total quantity of heat Q discharged through the layers 5 and 6 is divided into two components, i.e. heat flow Q, through bottom plate 2 and Q which is discharged through the outer mantle or steel wall 1.
  • Q may be about 200.000 kcal/h and Q may be about 240.000 kcal/h.
  • the temperature within the blast furnace is about l,400 to l,500C.
  • the isotherm for l,lC does not reach the top face of layer 4, which shows that no salamander will form and the bottom will not be attacked.
  • reference numeral 1 again indicates the steel mantle or outer wall of the furnace.
  • the layers of carbon graphite are also indicated by and 6.
  • a ramming mix indicated in FIG. 2 with reference numeral 10.
  • This ramming mix usually has a porosity of about 30 percent to 50 percent and is compressed when the furnace reaches operating temperature, by expansion of the bricks of the bottom layers 5, 6.
  • the heat conduction coefficient of copper is about 320 kcal/m/h/C. If e.g. at mutual distances of 25 cm a copper pipe is hammered in, having an outer diameter of 36 mm and an inner diameter of 32 mm, a double value of the total heat conductivity through the annular space is obtained as compared with the ramming mix alone about 5-l0).
  • the measure of the invention is not restricted to the said embodiment, but may as well be applied in other areas, such as near the wind holes, the bosh, the belly or cylinder and the lower part of the shaft or stack of a blast furnace, or for other furnaces.
  • a furnace provided with a wall and a refractory inner masonry structure, between which there is a space, characterized in that in this space compressible elements from a material with high heat conductivity are arranged in contact with the walls of said space.
  • a furnace provided with a wall and a refractory inner masonry structure, between which there is an annular space, characterized in that the refractory inner masonry structure and the wall are in heat conductive contact by the presence of elements of thermally good conductive material provided at regular intervals and compressible in a radial direction.
  • a furnace according to claim 3 characterized in that the surfaces bordering the said space have a somewhat converging configuration mutually, the largest distance between said surfaces being at most equal to the outer diameter of said pipes.
  • a furnace in particular a blast furnace for making pig iron, having liquid cooling along the outer periphery of the wall and air cooling of the bottom, said bottom having a horizontal layer of refractory material with a heat conduction coefficient A higher than 20 kcal/m/h/C under operating conditions, characterized in that this layer at the outer periphery is in heat conductive contact with the wall by the presence of elements of high thermal heat conductivity, compressible in a radial direction and arranged at regular intervals.
  • a furnace according to claim 5 characterized in that said layer consists of graphite with a heat conduction coefficient A of 60-100 kcal/m/h/C and that said elements consist of copper pipes.
  • a furnace in particular a blast furnace for making pig iron, in which the part of the bosh between the inner masonry structure and the wall is provided with a ramming mix or tamping mixture, characterized in that the radial heat conduction of the inner masonry structure to the wall is increased by providing elements of high thermal conduction in the ramming mix space, said elements being compressible in a radial direction.
  • a furnace according to claim 1 characterized in that the said wall of the furnace is embodied as the wall of a cooling space through which a cooling liquid can be passed.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • Blast Furnaces (AREA)
US00310719A 1971-12-01 1972-11-30 Furnace Expired - Lifetime US3788622A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2159667A DE2159667B2 (de) 1971-12-01 1971-12-01 Boden eines Hochofens für die Roheisenproduktion

Publications (1)

Publication Number Publication Date
US3788622A true US3788622A (en) 1974-01-29

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ID=5826735

Family Applications (1)

Application Number Title Priority Date Filing Date
US00310719A Expired - Lifetime US3788622A (en) 1971-12-01 1972-11-30 Furnace

Country Status (7)

Country Link
US (1) US3788622A (enrdf_load_stackoverflow)
BE (1) BE792108A (enrdf_load_stackoverflow)
DE (1) DE2159667B2 (enrdf_load_stackoverflow)
FR (1) FR2164218A5 (enrdf_load_stackoverflow)
GB (1) GB1407066A (enrdf_load_stackoverflow)
IT (1) IT1053711B (enrdf_load_stackoverflow)
LU (1) LU66566A1 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4325538A (en) * 1979-12-27 1982-04-20 Biuro Projektow Przemyslu Metali Niezelaznych "Bipromet" Smelting furnace for direct obtaining of copper from ore concentrates/and copper ores

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2819416C2 (de) * 1978-05-03 1984-04-05 Sigri Elektrographit Gmbh, 8901 Meitingen Feuerfeste Zustellung eines Schachtofens, insbesondere Hochofens
GB2143932A (en) * 1983-07-22 1985-02-20 Gordon Michael Priest Furnace
DE19816867A1 (de) * 1998-04-16 1999-10-21 Schloemann Siemag Ag Hochofen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3599951A (en) * 1968-11-27 1971-08-17 Inland Steel Co Blast furnace hearth

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3599951A (en) * 1968-11-27 1971-08-17 Inland Steel Co Blast furnace hearth

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4325538A (en) * 1979-12-27 1982-04-20 Biuro Projektow Przemyslu Metali Niezelaznych "Bipromet" Smelting furnace for direct obtaining of copper from ore concentrates/and copper ores

Also Published As

Publication number Publication date
DE2159667C3 (enrdf_load_stackoverflow) 1980-11-13
DE2159667B2 (de) 1980-03-20
LU66566A1 (enrdf_load_stackoverflow) 1973-02-01
GB1407066A (en) 1975-09-24
IT1053711B (it) 1981-10-10
BE792108A (fr) 1973-05-30
DE2159667A1 (de) 1973-06-07
FR2164218A5 (enrdf_load_stackoverflow) 1973-07-27

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