RU2140991C1 - Blast furnace - Google Patents

Blast furnace Download PDF

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Publication number
RU2140991C1
RU2140991C1 RU97115506/02A RU97115506A RU2140991C1 RU 2140991 C1 RU2140991 C1 RU 2140991C1 RU 97115506/02 A RU97115506/02 A RU 97115506/02A RU 97115506 A RU97115506 A RU 97115506A RU 2140991 C1 RU2140991 C1 RU 2140991C1
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Russia
Prior art keywords
furnace
blast furnace
segments
shaft
angle
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RU97115506/02A
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Russian (ru)
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RU97115506A (en
Inventor
Б.А. Марсуверский
М.И. Аршанский
С.В. Филатов
Б.П. Рыбаков
Г.С. Шибаев
С.П. Бастриков
А.В. Пархачев
В.А. Ходонецких
Е.В. Кучмистый
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ОАО "Нижнетагильский металлургический комбинат"
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Abstract

FIELD: ferrous metallurgy. SUBSTANCE: invention can be used in design of stack of blast furnace. Proposed blast furnace has metal segments filled with refractory lining in furnace top part and in upper part of its stack at height of one-three layers of burden loaded into blast furnace. Inclination angle of working surface of segments towards furnace axis is equal to 63-85 deg. Blast furnace also includes T-shaped supports mounted to prevent movement of metal segments in horizontal plane and to provide for their vertical movement. EFFECT: prolonged service life of brickwork of stack of blast furnace owing to its improved design. 2 cl, 2 dwg, 4 tbl

Description

 The invention relates to the metallurgy of ferrous metals and can be used in the construction of the mine blast furnace.
 A known design of a blast furnace, the lining of which contains metal segments in the top part and a refractory lining in the mine [1]. With this design, even in small blast furnaces, the height of the cylindrical part of the top reaches 2 m or more.
The disadvantage of this design is the occurrence of high lateral loads on the walls of the top, which leads to their wear and violation of the evenness of the descent of the charge materials. The height of the cylindrical part of the top equal to 2 m is excessive for medium volume furnaces. It should be such that the zone of materials loaded into the furnace is located within it, and the epicenter of the impact zone is in the upper 2/3 of the top. Therefore, for furnaces with a volume of up to 2700 m 3 , the height of the cylindrical part of the top is sufficient not more than 1.75 m, and its maximum height (for furnaces with a volume of 5000 m 3 and above) is up to 2.5 m.
 In design [1], attempts to reduce the height of the cylindrical part of the top lead to the destruction of the refractory masonry, located slightly below the metal segments, falling from the loading device materials. High lateral loads are created in the upper part of the mine with a decrease in the active weight of the charge column, the evenness of the melting of the melting materials is worsened, the use of chemical energy of the gas stream is reduced, the technical and economic performance of the furnace is reduced and its campaign is reduced.
Known for the design of a blast furnace, the lining of the upper part of the shaft of which is made of movable steel segments installed in a dressing and pivotally connected to the top [2]. This design eliminates the disadvantages of the above design, because due to the lower coefficient of external friction of iron ore materials on steel (f c = 0.330-0.360) than on refractory masonry (f o = 0.396-0.565), the convergence of charge materials occurs more evenly. The movement of the segments provides the necessary angle of inclination of the shaft wall when smelting cast iron from various types of raw materials. But the operation of the structure [2] is associated with significant difficulties in sealing the gap between the lining and the metal segments. Due to the failure to solve this problem, the stability of the movable segments at dp N 2 NTMK was only about 1 year.
 Of the known structures, the closest in technical essence is the lining of the blast furnace, containing blast furnace protection combined with the construction of the upper part of the shaft, suspended on rods to the dome of the furnace, and a refractory lining in the shaft [3]. Koloshnikovy protection is made of hollow steel small-sized segments (plates), interconnected and with the suspension bolts. The segments are turned into the furnace with a wall 100 mm thick, the cavities in them are filled with fireclay bricks on the mortar. Pendants are made in the form of knives from a metal sheet.
 The disadvantage of the prototype is that the movement of the protective plates in the vertical plane (due to thermal stresses) is very difficult due to the fastening of the segments on the bolts. Therefore, on MMK and KMK furnaces with such a lining, extension of segments in the direction of the top axis was observed, reaching 100-500 mm, associated with their expansion and plastic deformation, as well as with the deformation of the suspensions. The leaks were filled with zinc-containing deposits and the deformation of the segments intensified. As a result, the normal gathering of charge materials in the upper part of the furnace was difficult. The top protection had to be changed. The campaign of furnaces between major repairs of the III category was 2-3 years.
 The objective of the invention is to reduce friction between the wall of the shaft of the furnace and charge materials, as well as increasing the life of the masonry of the shaft by improving the design of the lining.
 The task is achieved in that the lining of the blast furnace contains metal segments in the furnace top and refractory masonry mine, characterized in that in order to reduce friction between the wall of the upper part of the mine and the charge materials loaded into the furnace, the upper part of the furnace shaft is lined with metal segments regardless of the furnace top to the height of one or two layers of materials loaded into the furnace, setting the segments on special supports.
The invention is illustrated by drawings:
FIG. 1 - shows a section of the upper part of the blast furnace;
FIG. 2 - the proposed design of the upper part of the mine blast furnace.
 The blast furnace consists of a casing 1, metal segments on the top 2 and in the shaft 3, and a refractory lining 4. The segments are held by supports 5, made in the form of a brand. To create density in the segments, they are filled with chamotte brick 6 on the mortar, and the gap 7 between the casing, segments and refractory masonry is filled with chrysotile asbestos. The supports 5 are located parallel to the casing and exclude the movement of the segments in the horizontal plane, but allow them to move vertically with thermal expansion of the refractory masonry 4. The cylindrical part of the segments from above is protected by the corner segments 8 from the incident charge flow from the loading device.
Segments 3 form the upper part of the shaft, the inclination angle α 1 of which is equal to the angle of external friction φ 1 of the charge materials in the furnace.
 The height of the shaft, lined with segments 3, is equal to one to three layers of the charge 9 from the portions loaded into the furnace.
It is known from practice that the height of the loaded portions of materials on blast furnaces with a useful volume of 1033-5000 m 3 at the top walls is 1.0-1.5 m. It is impractical to make segments in the shaft more than three meters high because of a decrease in structural stability in high areas temperatures and lateral loads [2].
According to research, the angle of repose φ o and external friction φ of charge materials in the absence of a gas stream is shown in table. 1 (see the end of the description).
In the conditions of blast-furnace smelting at a level of mound of 1.25 m, the angles φ o and φ decrease under the influence of a gas stream for sinter, pellets and coke, respectively, by 40.5; 31.2 and 38.1%.
Then the angle of inclination of segments 3 is equal to:
α 1 = 90 o1 . (1)
In modern blast furnace smelting, no more than 10% of iron ore is used, and coke is mainly loaded into the central and intermediate zones of the top radius. At the top wall are agglomerate and pellets. Therefore, the angle of inclination of the segments according to (1) should be within the range of α 1 = 78 o - 85 o on the working furnace, which is in good agreement with the angle of inclination of the mines of standard and advanced profiles.
On a stopped blast furnace, to prevent material crusting, the angle of inclination of the segments should be:
α 1 = 90 o -φ = 63 o -77 o (2)
The angle of inclination of the segments is less than 63 o when melting 100% of the agglomerate and less than 77 o when using 100% pellets, it is impractical to make, as voids will form between the flow of materials and the segments.
 A blast furnace with such angle of inclination of segments after long parking will be faster to reach full blast mode. We recommend making furnaces with such slope angles of segments that work with frequent stops and blow-ups (for example, due to the lack of raw materials or coke and their periodic accumulation).
In a mine with an angle of inclination of segments greater than 85 o when melting 100% of the pellets and above 78 o when using 100% of the agglomerate on intensively working furnaces, excessive lateral loads will be created that worsen the convergence of the charge and destroy the walls.
 When operating blast furnaces on a mixture of agglomerate and pellets, the angle of inclination of the segments should be set in accordance with the content of each component of the charge, as well as the frequency of operation and the duration of downtime.
 The portion of materials 9 loaded into the furnace is formed within the top. This creates lateral loads as a result of plastic deformation of the upper layer.
 Due to the lower coefficient of external friction of the charge on steel than on fireclay bricks, the charge layer sinks faster into the mine and tuyere pockets, increasing the intensity of blast furnace smelting, evenness of the furnace and the degree of utilization of the chemical energy of the gas stream.
An example of a specific implementation of the invention
The proposed technical solution was implemented at OAO Nizhny Tagil Metallurgical Plant in October 1995 at furnace No. 4 and in December 1995 at furnace No. 1 during the overhaul of II and I categories.
The upper part of the blast furnace shaft is shown in FIG. 2. Furnace No. 4 is oriented to the smelting of vanadium cast iron using an increased up to 70% fraction of pellets, and furnace No. 1 is oriented to the smelting of local Tagil-Kushvinsky agglomerates; therefore, the angle α 1 on the furnaces is 80 ° 25 'and 80 ° 05', respectively.
 Segments with a groove are installed in the supports in the form of a brand, and they are welded to the casing. Along the perimeter, the segments are pulled together by bolts.
 First, segments in the shaft were laid on the refractory masonry, and then segments in the cylindrical part of the top.
 A portion of materials dropped from a large cone is formed within the cylindrical part of the top. As a result of plastic deformation of the upper layer, maximum lateral loads are created. Due to the lower coefficient of external friction of the charge on steel than on refractory masonry, the lowering of the charge layers is accelerated, increasing the intensity of smelting along the melted ore rash and the evenness of the furnace, as well as the degree of utilization of the chemical energy of the gas stream.
 Technical and economic indicators of blast furnaces N 4 and 1 during the smelting of vanadium cast iron before and after the implementation of the proposed technical solution are presented in table. 2 and 4. The degree of use of carbon monoxide in blast furnace gas increased from 0.463 to 0.481 and from 0.405 to 0.461.
 For blast furnace No. 4, the compared periods should be taken with a small time gap caused only by the repair of category II and the output of the furnace to the planned melting indices.
 In connection with the long-term repair (18 months) of the blast furnace No. 1 and unsatisfactory melt performance before repair, the time gap between stable operation in the control and experimental periods was more than 4 years.
 After adjusting the smelting indices for blast furnaces N 4 and 1 to the same conditions (Tables 2 and 4), the specific consumption of coke in the periods with the introduction of a new technical solution decreased by 0.4 and 5.1%, respectively.
 Due to the insufficient amount of raw materials and a significant deterioration in the quality of coke in period 2, blast furnace N 1 reduced the smelting intensity by replacing air tuyeres 160 by 140 mm, therefore, its adjusted productivity remained approximately the same (Table 5).
 On blast furnace No. 4, the change in the melting conditions was not as significant as furnace No. 1, therefore, its productivity after the introduction of advanced blast furnace protection increased by 4.8% (Table 3).
 Thanks to the proposed technical solution, the technical and economic performance of the blast furnace is improved (see table. 2-5).

Claims (3)

1. A blast furnace containing metal segments filled with refractory lining in the top and top of the shaft of the furnace and refractory lining of the shaft, characterized in that it is equipped with supports in the form of a tee mounted to exclude the movement of metal segments in a horizontal plane and ensure their vertical movement, the metal segments in the upper part of the shaft are made at the height of one to three layers of the charge from the portions loaded into the furnace with the angle of inclination of their working surface to the axis p chi, equal to 63 - o 85.
2. Blast furnace according to claim 1, characterized in that for intensively working furnaces the angle of inclination is 78 - 85 o .
3. The blast furnace according to claim 1, characterized in that for furnaces with frequent stops and blow-ups, the angle of inclination is 63 - 77 o .
RU97115506/02A 1997-09-17 1997-09-17 Blast furnace RU2140991C1 (en)

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RU97115506/02A RU2140991C1 (en) 1997-09-17 1997-09-17 Blast furnace

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RU2140991C1 true RU2140991C1 (en) 1999-11-10

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Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Дружков В.Г. и др. Служба колошниковых защит доменных печей. - Металлург, 1980, N 2, с.13-14. *

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Effective date: 20040918