US3811868A - Method for charging materials into blast furnace - Google Patents

Method for charging materials into blast furnace Download PDF

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Publication number
US3811868A
US3811868A US00286886A US28688672A US3811868A US 3811868 A US3811868 A US 3811868A US 00286886 A US00286886 A US 00286886A US 28688672 A US28688672 A US 28688672A US 3811868 A US3811868 A US 3811868A
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Prior art keywords
furnace
charging
materials
coke
charged
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Expired - Lifetime
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US00286886A
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English (en)
Inventor
S Inaba
S Tamura
T Uenaka
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Kobe Steel Ltd
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Kobe Steel Ltd
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B7/00—Blast furnaces
    • C21B7/08—Top armourings

Definitions

  • FIG. 1 Claims, 15 Drawing Figures PATENTED M Mill? FIG. 1
  • PATENTEBIAY 2 1 m4 SHEEI 5 BF 7 FURNACE HALL/ PERMIABILI TY INDEX K ((65 UNI T5) FIG. 7
  • This invention relates to a method of charging iron ore or iron bearing materials such as iron ore pellets, sintered ores, etc., and a solid reducing material such as coke to a furnace byway of a variable charging means such as an armor plate or collision plate located in an upperregion of the blast furnace so that the ore coke ratio in the stock will be substantially uniform in the radial direction of the furnace.
  • a variable charging means such as an armor plate or collision plate located in an upperregion of the blast furnace so that the ore coke ratio in the stock will be substantially uniform in the radial direction of the furnace.
  • Another object of the present invention is to provide a method for charging stock material into a blast furnace whereby the ore-coke ratio in the radial direction is rendered substantially uniform by controlling the charging positions such that the circular vertices of both layers of the solid reducing materials are located in the radial direction of the furnace between the circular vertex of one layer of an iron bearing material and the circular vertex of a second layer of iron bearing materials. This results in a stabilized and highly efficient blast furnace operation.
  • a second step consisting of the charging of a solid reducing material C followed by the forward charging of an iron bearing material 0
  • Both circular vertices of'the layers of the solid reducing materials C. and C are located in the radial direction of the furnace between the circular vertex of the iron bearing material 0 and the circularvertex of the iron bearing material 0
  • the vertex positions in the two accumulated layers of an iron material and a solid reducing material are formed in one cycle of a charging operation, wherein each cycle comprises the following two steps:
  • the first step consists of charging a solid reducing material C, followed by the backward charging of an iron bearing material 0
  • the vertex of the 0, layer is located closer to the furnace core or wall than the vertex of the layer of said solid reducing I material C, already added to the furnace;
  • the second step consists of charging a solid reducing material C followed by the forward charging of an iron bearing material 0
  • the vertex of the O layer is located closer to the furnace wall, if 0, is located next to the core, than the vertices of the layers of said solid reducing materials C, and C already added to the furnace.
  • the vertex of layer r 0 is located closerto the core, if 0 is located next to the furnace wall, than the vertices of the layers of said reducing materials.
  • FIG. 1 is a partial, vertical, sectional view of a model blast furnace
  • FIGS. 2A, 2B and 2C are schematic illustrations showing the sequential mode of entry of the falling charge material and the mode of accumulation of the pellets of iron bearing material in the furnace;
  • FIG. 2 is a schematic illustration showing the mode of entry of the falling charge material and the mode of accumulation of the sintered grains of iron bearing material in the furnace;
  • FIGS. 4 and 5 are graphs showing the radial ore/coke distribution patterns in the furnace as observed when the charging position of the coke in the model blast furnace is fixed while the pellet and sintered grain charging positions are varied;
  • FIG. 6 is a series of graphs showing the radial ore/- coke distribution patterns in the furnace as observed when the pellet and sintered grain charging positions are fixed while the coke charging position is varied;
  • FIG. 7 is a diagram which shows the manner of entry of the falling material and the accumulation of material as the materials are charged according to the method of the present invention
  • FIG. 8 is two graphs showing the ore/coke distribution patterns-obtained when the materials are charged as pellets or sintered grains according to the present method
  • FIGS. 9 and 10 are graphs showing the variation of the permeability index in the radial direction of the furnace as observed when the materials are charged according to a conventional method and according to the present method, respectively;
  • FIGS. 11 and 12 are graphs showing gas compositions and temperature profiles in the radial direction in the stock in an upper region of the furnace as observed in actual operations, respectively, of a conventional method and of the present method.
  • FIG. 13 is a series of graphs showing the fuel ratio and the number of times of slipping in the actual operations of a conventional method and of the present method, respectively.
  • Pellets and sintered grains were mainly used as iron bearing materials in the experiments. These materials lately, have become of major interest in the metallurgical industries. Coke was used as the solid reducing material in the process of this invention. A movable armor plate coaxially disposed with the furnace core in an upper region in the interior of the furnace was employed as a means for controlling the distribution of the charge materials.
  • the experiments and test operations were conducted under two conditions. In the first test, a model reduced in size to l/ 10 the actual blast furnace size was used, while in the second test, an actual. large-sized blast furnace was used.
  • FIG. 1 shows a vertical section of a portion of this apparatus, comprising a large bell (1), a hopper (2) and an armor plate (3) which is freely movable in a lateral direction to the furnace wall (4) and to the furnace core (5) within the distance between points (A) and (B), and which is coaxially disposed with respect to the furnace core (5).
  • the distance (A to B) through which the bottom end of the armor plate (3) is radially movable was divided equally into 10 sections.
  • the mode of entry of the falling materials and the mode of accumulation of the materials charged into the furnace were observed by changing the position of said plate between the 10 sections.
  • the radial distribution patterns of the iron bearing materials and coke in the furnace were determined by sampling each' of said materials by a tubular sampling device (not shown), and then analyzing them.
  • the grain sizes of the charged materials used in this portion of the experiments were about l/5 of those used in a real blast furnace.
  • the pellets used in the experiments possessed a grain size from I to 5 mm.
  • the sintered grain sizes ranged from 3 to 10 mm.
  • the coke particle sizes ranged from 5 to 15 mm. 4
  • the distribution patterns exhibited by the various kinds of accumulated materials in the upper portion of the blast furnace assumed an M shape, a V shape or some other similar shape depending on the sectional configuration of the stock line.
  • the pellets demonstrated a peculiar behavior, as described below, when charged into the furnace.
  • the pellet charge (7) which has fallen on the coke layer (6) is biased toward the furnace wall (4).
  • the falling particles impinge upon the surface of the accumulated materials, they quickly spill over the crest and force the upper portion of the coke layer down the slope toward the furnace core (5) (see FIG. 2A).
  • the force of theflow of particles causes the coke in the central area (the area halfway between the furnace wall and the core) to flow toward the furnace core and form a shelf (8) of coke in the central area closer to the furnace core.
  • This shelf terminates as a mixed layer composed mainly of coke having a long slope which prevents a succeeding charge of pellets from flowing toward the furnace core (see FIG. 2B).
  • the slope of the pellet layer (7) is gradually increased.
  • an avalanche of particles flows down from the vertex towards the core of the furnace.
  • the shelf (8) has alarg'e slope which is built up at a middle point and is biased toward the furnace core. This shelf is engulfed in the pellet flow and is forced with said pellet flow toward the furnace core, so that the ore-coke ratio in the stock near the furnace core (5) is lowered.
  • the ore-coke ratio is relatively increased in the region of the shelf as a result of the damming of the pellets by the shelf. This phenomenon occurs no matter at what position and at what angle the armor plate is set. It also occurs when no armor plate is used.
  • a coke-sinter mixture layer (9) is formed near the furnace core portion, and since the sintered grain accumulation line is relatively close to a straight line as compared to the .ore pellet case where the coke accumulation curve possesses a concave configuration between the central region of the furnace and the furnace core and describes a large circular arc, the ore-coke ratio is also increased in the central region close to the furnace core as in the case of the ore pellets. Also, since the sinter mass is spongy and deformable, the ore-coke ratio may be excessively increased in the neighborhood of the furnace wall, depending upon the position of the armor plate.
  • FIG. 4 shows the ore/coke distribution patterns in the radial direction in the furnace as witnessed when the coke and pellets are charged alternately by fixing the position of the armor plate relative to the coke while varying the position of said plate relative to the pellets.
  • FIG. 5 shows the patterns obtained when sintered grains are used.
  • the figures labeled with the letters P and S indicate the armor plate positions set for the charging of pellets and sintered grains, respectively. As the number adjacent the letter Por S in the figure is increased, the amount of material charged toward the furnace core correspondingly increases.
  • FIG. 6 shows the ore/coke distribution patterns ob served when the position of the armor plate set for the pellets and sintered grains is fixed while varying its position for the charged coke.
  • FIGS. 4 to 6 indicate that in order to obtain an optimum operation from a uniform ore/coke distribution in the blast furnace, the charging position of the solid reducing material (coke) should not be widely separated from the charging position of the pellet or sintered grain iron bearing material.
  • the graphs also indicate that optimum performance is more sensitive to the charging position of the iron bearing materials than the solid reducing material. Thus, more care must be exercised in controlling the addition of the iron bearing materials.
  • the conventional charging method in which the materials are repetitively charged through fixed charging positions of both the solid reducing material and the iron bearing material (one charging cycle of this method will be expressed hereinafter as a 'C l O 1 pattern), has been obviated.
  • a new charging method is employed in which the iron bearing material charging position is not fixed relative to that of solid reducing material, but is varied between two locations so that the iron bearing material is alternately charged from these two locations (one charging cycle of this new method is expressed as a C iO lC 1O 1 pattern).
  • the iron bearing materials 0 and 0 are accumulated in the furnace in such a manner that the vertices of the layers will be located more closely either to the core side of the furnace and then the wall side of the furnace, or to the wall side of the furnace and then the core side of the furnace, than the vertices of the layers of solid reducing materials C and C which have accumulated in the furnace.
  • the vertices of the iron bearing material 0 and 0 layers be located more closely to the furnace wall or core with the vertices of the solid reducing materials C and C layers located between the vertices of the iron bearing material layers in the radial direction of the furnace.
  • the armor plate is first set at the charging position to charge the solid reducing material C, to form a firs circular vertex having a given radius.
  • the plate is set at 0 that iron material 0 will be charged biased towar the furnace wall (4) relative to C, to form a second circular vertex having a radius greater than said given radius, and then set atg pso that the solid reducing material C will be charge more closely toward the furnace core (5) than 0, to form a third circular vertex having a radius less than the radius of aid second circular vertex.
  • the plate is set at :0 that iron material 0 will be charged biased towar the furnace core (5) relative to C and C to form a fourth circular vertex having a radius less than said first and third circular vertices.
  • FIG. 9 shows the permeability index variation patterns demonstrated by a conventional ClO lcharging method where the pellet and sintered grain charging positions are set on the furnace core side and on the furnace wall side with respect to the coke charging position.
  • FIG. shows the penneability index variations obtained by the method of the present invention in which charging of the furnace was conducted by combining the respective CiOlcharging patterns of iron pellets and sintered grains in a cyclic charging pattern of: C,1O,1C 1O 1(C,1P,1C lP tor C, ts lC lst).
  • the permeability index (L) is determined by the pressure loss (AP) in the bed. L represents the height of the bed, p.
  • the ore/coke distribution in the furnace as well as the permeability index is rendered highly uniform. This allows a more uniform and more effective utilization of the gas flow in the furnace for treatment of the charged materials.
  • the invention has been described centering around the mode of entry of the falling material and the mode of accumulation of the charged materials in the radial direction of the furnace and the concomitant gas flow distribution pattern, based on the experimental results obtained by practicing the invention in a model laboratory apparatus. Now, the actual performance of the present invention as used in a full scale blast furnace is described in comparison with the prior art methods.
  • the furnace used in the tests was a large-sized blast furnace having an interior capacity of 2,843 m Charging tests were conducted by using to 75 mm-size coke particles as the solid reducing material, and 5 to mm-size pellets as the iron bearing material.
  • the furnace was provided with a movable armor plate in an upper part of the shaft, a sampling device for determining gas compositions (C0, C02), and a means for determining the temperature distributions in the charged material layers in the upper regions of the furnace.
  • the positions of the armor plate were determined in the same manner as in the case of the model furnace by dividing the radially movable range in the furnace equally into 10 sections. The position closest to the furnace wall side was designated as the 0 position and the position closest to the core side was designated as the l 0 position.
  • FIG. 11 are shown the gas compositions and the temperature distributions in the stock in the upper region of the furnace as observed when a repeating C i0 1(C1Pl) charge pattern was employedaccording to a conventional method. Charging of the materials was conducted by setting the armor plate at position 6 (C 6) for the coke and at position 4 (P 4) for addition of the iron containing pellets.
  • FIG. 12 shows the gas compositions and temperature distributions obtained when a 0, 0, 0,10, catamaran charge pattern was employed according to the method of the present invention. The armor plate positions were at 6 for coke (C C and at 3 and 7 for pellets P. and P respectively.
  • the ore/coke ratio in the stock material in the furnace is confined within a small range rendering the gas flow and temperature distributions uniform. Also, the reduction of the iron oxides in the furnace is expedited (causing a decline in the fuel ratio), allowing a smooth drop of the furnace charge and stabilized furnace conditions. This results in a minimum of slipping and a minimum of damage to the tuyeres and other elements in the furnace. Thus, an extremely efficient and economical blast furnace operation is realized.
  • pellets and sintered grains were used as the iron raw materials, but it was found that many other types of iron ores exhibit similar behavior. Their behavior is not as striking as the behavior of the pellets, but they can be used to accomplish the objectives of the present invention. Also, although in the embodiments shown, an armor plate was used as the material charging means, it is possible to use any other means provided that said means is Capable of charging the materials to the furnace core and its charging position is freely adjustable in the radial direction in the furnace.
  • a method for charging materials into a blast furnace having a variable charging means for alternately charging solid reducing materials and iron bearing materials to form layers having coaxial circular vertices which comprises:
  • a first step consisting of the charging of a solid reducing material (C to form a first circular vertex having a given radius followed by charging of an iron bearing material (0,) to form a second circular vertex having a radius greater than said given radius and,

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture Of Iron (AREA)
US00286886A 1972-03-06 1972-09-07 Method for charging materials into blast furnace Expired - Lifetime US3811868A (en)

Applications Claiming Priority (1)

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JP2289672A JPS5610363B2 (OSRAM) 1972-03-06 1972-03-06

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US (1) US3811868A (OSRAM)
JP (1) JPS5610363B2 (OSRAM)
AU (1) AU444595B2 (OSRAM)
BR (1) BR7207250D0 (OSRAM)
CA (1) CA969760A (OSRAM)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS643559U (OSRAM) * 1987-06-24 1989-01-10
JPH0334768U (OSRAM) * 1989-08-11 1991-04-04
JP6303685B2 (ja) * 2014-03-25 2018-04-04 新日鐵住金株式会社 ベルレス高炉の装入物装入方法

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AU4644072A (en) 1974-01-31
JPS5610363B2 (OSRAM) 1981-03-07
BR7207250D0 (pt) 1973-12-13
AU444595B2 (en) 1974-01-31
JPS4890913A (OSRAM) 1973-11-27
CA969760A (en) 1975-06-24

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