RU2722947C1 - Blast furnace profile for high-intensity operation - Google Patents

Abstract

FIELD: blast furnaces.SUBSTANCE: blast furnace comprises casing, refractory lining, hearth bottom, cylindrical hearth and tapholes for outlet of fusion products. Useful height h, diameter dand "dead layer” height hof hearth correspond to the following relationships: h/d=(0.45–0.50), d/D=(0.80–0.85), hH=(0.35–0.40), where Dis the diameter of the furnace waist; Nis the full height of the hearth. Refractory lining of cylindrical hearth in horizontal section in the area of tapholes is made in the form of segment with increased thickness, equidistant from the axis of tapholes by an angle α equal to 20–35°.EFFECT: as a result, wear of lining of hearth and shaft is reduced, specific consumption of fuel, oxygen and refractory materials is reduced.1 cl, 2 dwg

Description

The invention relates to the field of ferrous metallurgy, in particular to the design of a blast furnace, mainly with a useful volume of more than 1500 m ³ .

To create the most favorable conditions for all processes in a blast furnace, the profile configuration is of great importance, which ensures uniform gathering of the loaded charge materials, a given distribution of materials and gases over the cross section and their residence time in the furnace, and the transition of materials from solid to liquid without deterioration lowering the charge column, the accumulation of smelting products in the lower part of the furnace.

Various blast furnace profiles are known in the art.

The known profile of the blast furnace [1] Vegman EF, Zherebin BN, Pohvistnev A.V. and others. Iron metallurgy. The textbook for high schools.-M .; "Metallurgy", 1989. With 355, where the hearth diameter d _G is determined depending on the intensity of coke burning in the tuyeres and corresponds to the ratio

D / d _G = 1.10 ÷ 1.15

where D is the diameter of the steam (m);

(1.10 ÷ 1.15) - empirical coefficients;

and the hearth height h _g is determined depending on the amount of smelting products and, in general, to the lower edge of the shoulders and is:

h _G = h _f + a,

where h _g is the height of the hearth (m);

h _f - the height of the air lance above the axis of the cast iron notch (m);

a = 0.4 ÷ 0.5 design size (m),

the height of the air tuyeres above the axis of the cast iron notch is determined from the formula:

h _f = PV _G / F,

where h _f - the height of the air lance over the axis of the cast iron notch (m);

P - blast furnace productivity (t / day);

V _g - the volume of the hearth from the axis of the cast iron notch to the axis of the air tuyeres per 1 ton of daily smelting (m ³ · day / t);

F - hearth cross-sectional area (m ² ).

The disadvantage of this profile is the deterioration in the stability of the thermal state of the blast furnace with an increase in the intensity of cast iron smelting and the disruption of the interaction of the increased formation of liquid smelting products with coke packing, a decrease in the stability of the chemical composition of cast iron and slag.

The closest in technical solution is a blast furnace [2] (Patent RU No. 2263150 “Blast furnace” IPC ⁶ C21B7 / 06, publ. 10/27/2005, Bull.No. 30), containing a hearth, a discharge let and a flask with at least three layers of refractory lining, while the outer surface of the bream is located below the level of the groove by H = (0.9 ÷ 1.1) * (750d-22d ² -3000) (m), the height of the bream is N _D and the thickness of the hearth wall (b ) associated with a flare correspond to the following relations:

7000)-Н (м),N _D = (4000

7000) -N (m),

b = (0.05 ÷ 0.15) * d,

where d is the inner diameter of the surface of the bream (m);

(0.9 ÷ 1.1), 22, 750, 3000, (4000 ÷ 7000), (0.05 ÷ 0.15) - empirical coefficients.

The disadvantage of this profile of the blast furnace is the insufficient stability of the space around the year, the lack of improved conditions for the formation of a skull in the lower part of the mine, the drainage of fusion products and stabilization of the outflow of materials in the hearth, as well as the ratios for determining the height of the “dead layer” of the hearth are insufficient for blast furnaces operating with increased specific productivity.

The technical result of the present invention is to reduce the wear of the lining of the hearth and mine; boosting the furnace campaign; increase furnace productivity and improve the technical and economic indicators of blast furnace smelting, such as a decrease in the specific consumption of fuel, oxygen and refractory materials; increasing the stability of the thermal state of the blast furnace and improving the quality indicators of cast iron; reduction in the volume of work and the duration of major repairs.

The specified technical result is achieved by the fact that in a blast furnace containing a casing, a refractory lining, a flask, a hearth and a tap hole, the following differences are provided: usable height h _G , diameter d _G and the height of the “dead layer” h _MC hearth correspond to the following ratios: h _G / d _Г = 0.45 ÷ 0.50, d _Г / D _P = 0.80 ÷ 0.85, h _{MC /} Н _Г = 0.35 ÷ 0.40, and the refractory lining of the cylindrical hearth in horizontal section in the region the notch is made in the form of a segment with increased thickness equidistant from the axis of the notch 9 by an angle α equal to 20–35 °.

In addition, in the proposed profile of the blast furnace, the angle of inclination of the shoulders β is 73-77 ° and is set based on the height of the shoulders H _Z , which corresponds to the ratio:

N _{W /} D _P = 0.30 ÷ 0.37,

where h _G is the effective height of the hearth;

d _G - hearth diameter;

D _P is the diameter of the steam;

h _MC - the height of the "dead layer" of the hearth;

N _G - full height of the hearth;

α is the angle from the axis of the notch to the side of the central angle of the chord of the refractory lining segment in the notch area;

β is the angle of inclination of the shoulders;

N _W - the height of the shoulders;

(0.45 ÷ 0.50), (0.80 ÷ 0.85), (0.35 ÷ 0.40), (0.30 ÷ 0.37) are empirical coefficients.

The invention is illustrated by drawings, which depict:

Figure 1 is a vertical section of the hearth and shoulders of a blast furnace;

Figure 2 is a horizontal section of the hearth of a blast furnace at the level of a notch.

A blast furnace consists of: a casing 1, a refractory lining 2, a bream 3, a hearth 4, tap holes for the release of smelting products 5, a cylindrical refractory lining of the hearth 6, a refractory lining of the hearth in the area of the doors, made in the form of segment 7, shoulders 8.

In blast furnaces with an increase in the intensity of pig iron smelting, the most acute question arises of compensating for the increased wear of the elements of the blast furnace and increasing the overhaul period.

The usable height h _{G of the} hearth 4 shown in FIG. 1 is determined by the ratio to the diameter of the hearth h _G / d _G = 0.45 ÷ 0.50, and the diameter of the hearth d _G is determined by its ratio to the diameter of the steam d _G / D _P = 0.80 ÷ 0.85,

where h _G is the effective height of the hearth 4 (m);

d _G - hearth diameter 4 (m);

D _P is the diameter of the steam (m);

(0.45 ÷ 0.50), (0.80 ÷ 0.85) are empirical coefficients.

With a high intensity of smelting and increased formation of liquid smelting products, an increase in the height of the hearth h _G with a decrease in its diameter d _G provides a more complete interaction of the smelting products with the coke nozzle, which contributes to uniform drainage of the liquid smelting products with the full cross section of the hearth and stabilization of the thermal regime with the lowest fuel and energy costs creates the conditions for the completion of recovery processes, and also reduces the negative impact of factors affecting burnout tuyeres “from below”.

The height of the "dead layer" h _{MC of the} hearth 4 of the blast furnace, shown in FIG. 1, is measured from the axis of the slots 9 to the bottom 3 and is determined by the following ratio: h _{MC /} H _G = 0.35 ÷ 0.40,

where h _MC - the height of the "dead layer" of the hearth 4;

N _G - full height of the hearth 4;

(0.35 ÷ 0.40) - empirical coefficients.

Increasing the height of the "dead layer" h _MC hearth 4 allows you to stabilize the thermal state of the blast furnace and the chemical composition of the smelting products due to the greater volume of pig iron in the furnace below the axis of the slots 9.

The refractory lining 6 of the cylindrical hearth 4 in horizontal section in the area of the grooves 5 shown in FIG. 2 is made in the form of a segment 7 with an increased thickness equidistant from the axis of the groove 9 by an angle α equal to 20 ÷ 35 °. In this case, the coupling of the cylindrical part of the lining 6 with the lining in the form of a segment 7 is recommended to be smoothed, but not required.

Changing the configuration of the refractory lining 7 in the area of the grooves 5 prevents the free formation of vortex flows of the melting products due to the chordic change in the cross section of the hearth 4, and thereby reduces the wear of the lining of the hearth 4, which allows to increase the overhaul period and the campaign of the blast furnace as a whole. As well as the use of this configuration of the lining in the form of segments 7 in the area of letok 5, it is possible to stabilize the course of releases of smelting products and reduce the consumption of in-flight refractory mass for the restoration of the space around the year.

The angle of inclination β of the shoulders 8, shown in FIG. 1, is 73-77 ° and is set based on the height of the shoulders H _Z , which corresponds to the ratio of N _{W /} D _P = 0.30 ÷ 0.37,

where β is the angle of inclination of the shoulders;

D _P is the diameter of the steam (m);

N _Z - the height of the shoulders (m);

(0.30 ÷ 0.37) - empirical coefficients.

For modern blast furnaces, the angle of inclination β of the shoulders 8 is taken within 79-82 ° [1] (Wegman EF, Zherebin BN, Pokhvistnev A.V. et al. Metallurgy of cast iron. Textbook for universities.-M. : "Metallurgy", 1989. With 355). In the present invention, the angle of inclination β of the shoulders 8, shown in FIG. 1, is reduced to 73-77 °, which ensures the formation of the optimal gas flow (gas permeability) and column of materials, allows to stabilize the gathering of materials in the furnace 4 in conditions of increased specific productivity of the blast furnace, and also provides the formation of a stable skull in the lower part of the shaft of the blast furnace, which reduces heat loss and wear of the refractory lining of the blast furnace.

In addition, the use of this profile of the blast furnace allows the formation of a stable uniform skull (without distorting the design profile of the furnace), which allows you to abandon the additional lining (by spraying or otherwise) with refractory materials of the furnace shaft during periods of major repairs, which reduces the amount of work, duration of repair and consumption of refractory materials.

In contrast to the profile of the blast furnace [2] (patent RU No. 2263150 “Blast furnace” IPC ⁶ C21B7 / 06, published October 27, 2005, Bull. No. 30) in the developed design of the profile of the blast furnace, the furnace has a horizontal refractory lining in the horizontal section increased thickness of the letlet, equidistant from the axis of the letlet by an angle α equal to 20-35 °, the calculation of the value from the flak to the axis of the letlet (dead layer) is determined by its ratio to the full hearth height h _{MC /} Н _Г = 0.35 ÷ 0.40 and is outside the formula for this analogue N = (0.9 ÷ 1.1) · (750d-22d ² -3000). In addition, the design of the hearth and shoulders is determined by the following relationships:

h _G / d _G = 0.45 ÷ 0.50, d _G / D _P = 0.80 ÷ 0.85, h _{MC /} N _G = 0.35 ÷ 0.40,

N _{W /} D _P = 0.30 ÷ 0.37;

where h _G is the effective height of the hearth (m);

d _G - hearth diameter (m);

D _P is the diameter of the steam (m);

h _MC - the height of the "dead layer" of the hearth (m);

N _G - full height of the hearth (m);

α is the angle of inclination of the shaft;

β is the angle of inclination of the shoulders;

N _Z - the height of the shoulders (m);

(0.45 ÷ 0.50), (0.80 ÷ 0.85), (0.35 ÷ 0.40), (0.30 ÷ 0.37) are empirical coefficients.

The application of the proposed blast furnace profile provides:

reduced wear of the lining of the hearth and mine;

- increase the campaign of the furnace;

- increase the productivity of the blast furnace;

- improvement of technical and economic indicators of blast furnace smelting (fuel economy, reduction of oxygen consumption and consumption of refractory materials);

- improving the stability of the thermal state of the blast furnace;

- increasing the stability of the chemical composition;

- improving the quality indicators of cast iron;

- reduction in the volume of work and the duration of major repairs.

The analysis of the prior art, including the search by patents and scientific and technical information and the identification of sources containing information about analogues of the claimed technical solution, allowed us to establish that the applicant did not find sources characterized by features identical to all the essential features of the claimed invention.

Therefore, the claimed invention meets the criteria of "novelty" and "inventive step".

Sources of information

[1] Vegman EF, Zherebin BN, Pokhvistnev A.V. and others. Iron metallurgy. Textbook for high schools. - M .: "Metallurgy", 1989. With 355.

[2] Patent RU No. 2263150 "Blast furnace", IPC ⁶ C21V7 / 06, publ. 10/27/2005, Bull. Number 30.

Claims (2)

1. A blast furnace containing a casing, a refractory lining, a flask, a cylindrical hearth and tap holes for the production of melting products, characterized in that the usable height h _G , diameter d _G and the height of the "dead layer" h _MS hearth correspond to the following ratios: h _G / d _G = (0.45-0.50), d _G / D _P = (0.80-0.85), h _{MS /} N _G = (0.35-0.40), where D _P is the diameter swing; N _G is the full height of the hearth, while the refractory lining of the cylindrical hearth in a horizontal section in the area of the grooves is made in the form of a segment with an increased thickness equidistant from the axis of the grooves by an angle α equal to 20-35 °. 2. A blast furnace according to claim 1, characterized in that the angle of inclination of the shoulders β is 73-77 ° and is set based on the height of the shoulders H _Z , which corresponds to the ratio H _Z / D _P = 0.30-0.37.

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