RU2299243C1 - Blast furnace tuyere - Google Patents

Abstract

FIELD: metallurgy, namely structures of blast furnace tuyeres.

SUBSTANCE: tuyere of blast furnace includes mutually joined flange, outer and inner housings and nozzle part with cooling ducts. Total surface area of cross sections of cooling ducts consists of 0.07 - 0,54 of cross section area of wall of tuyere nozzle part. Spacing from inner surface of cooling duct till outer surface of nozzle part of tuyere consists of 0.05 -0.50 of thickness of nozzle part wall in zone of cooling duct arrangement. Spacing between inner surfaces of adjacent cooling ducts along axis of tuyere consists of 0.01 -0.60 of length of nozzle part of tuyere.

EFFECT: improved strength of tuyere.

5 cl, 2 dwg, 1 ex

Description

The invention relates to the metallurgy of ferrous metals, in particular to the designs of the tuyeres of blast furnaces.

To improve the durability of the tuyeres of blast furnaces, many different options were proposed. For example, the tuyere of a blast furnace is known, containing a water-cooled casing, consisting of an inner and outer conical cups connected by an end with a flange and with a snout (AS USSR No. 870433, publ. 07.10.1981). Also known is the tuyere of a blast furnace containing a water-cooled case, consisting of an outer and inner shell with a flange and a snout, in the cooled cavity of which there is a tube with a tangentially directed nozzle for supplying a cooler, a pipe for its removal and an annular perforated partition (A.S. USSR No. 1027216, publ. 07/07/1983).

A common disadvantage of both known tuyeres is their low resistance due to insufficient cooling of the tuyeres in the back part.

Closest to the claimed one is the tuyere of a blast furnace containing interconnected flange, outer and inner cases and the back part with a filled coil (Kudinov G.A. Cooling of modern blast furnaces. - M .: Metallurgy, 1988. P.241-243) .

A disadvantage of the known lance is its low resistance, since the size of the cooling channels of the snout of the lance is not regulated, depending on the section of the wall of the snout.

EFFECT: increased lance resistance.

The technical result is achieved in that the tuyere of the blast furnace containing interconnected flange, the outer and inner bodies and the back part with cooling channels in the form of a coil is characterized by the fact that the total cross-sectional area of the cooling channels with a longitudinal axial section of the back part of the tuyere is 0.07 ÷ 0.54 from the cross-sectional area of the wall of the back of the tuyere, and the distance from the surface of the cooling channel to the outer surface of the back of the tuyere is 0.05 ÷ 0.50 of the wall thickness of the back of the tuyere ala. The distance between the surfaces of adjacent channels in the direction of the axis of the lance is 0.01 ÷ 0.60 of the length of the back of the lance. In special cases, the internal channels can form a flooded pipe, as well as a profile of square or rectangular section. The flange, the outer and inner shells and the snout are interconnected by welds.

The drawing shows the tuyere of a blast furnace: figure 1 is a longitudinal section and figure 2 is a left view.

The lance contains a pipe for supplying water 1, a flange 2 connected to the outer 3 and inner 4 cases, which are connected on the other side to the back part 5, into which the coil 6 is filled, also contains a pipe 7 for supplying gas and a pipe 8 for draining water. The letters indicate: d is the inner diameter of the coil tube (cooling channel); S is the wall thickness of the back of the lance at the location of the coil; L is the length of the outer muzzle of the lance; a is the distance between the surfaces of two adjacent coils of the coil tube (cooling channels); b is the distance from the inner surface of the pipe coil (cooling channel) to the outer surface of the snout of the lance.

Tuyere works as follows. The cooler through the pipe 1 is fed into the coil 6, filled in the back of the pipe 5. The pipe 1 passes through the flange 2 and the rear chamber, which is limited by the outer 3 and 4 inner bodies. The pipe 1 is a continuation of the flooded coil 6. The cooler passes through the coil 6, cools the back part 5 and is discharged into the rear chamber, limited by the outer 3 and inner 4 cases. After cooling the back chamber, water is discharged through the pipe 8. During operation of the lance in the blast furnace, gas is supplied through the pipe 7.

The operation of an air lance consists in supplying hot blast to the furnace of a blast furnace to maintain the burning of coke. Sources of heat acting on the lance, in addition to hot blast, are also thermal radiation from the furnace hearth and liquid smelting products in contact with the lance. In this case, the strongest thermal effect, which may result in penetration of the tuyere wall, is exerted by molten iron.

In connection with difficult operating conditions, the claimed lance design has several advantages, which include more intensive cooling of the front and outer surfaces of the front part, where thermal loads reach maximum values. The intensification of cooling is achieved by using a coil with a predetermined section of the cooling channels in the snout section. Moreover, in the particular case, to reduce the thickness of the tuyere wall in the back part of the coil, the coil is made in the form of a two-way spiral.

It was experimentally established that in order to increase the lance resistance, the total cross-sectional area of the cooling channels with a longitudinal axial cross-section of the tuyere tuyere part should be 0.07 ÷ 0.54 of the cross-sectional area of the tuyere tuyere wall section. With a smaller value of the cross-sectional area of the channels, the back of the channel quickly overheats and the lance fails, since the channels of a small section do not provide the necessary cooling of the back of the channel. With a larger value of the cross-sectional area of the channels, they become bulky, occupy a large wall area, and, as the ryl part wears out, a burn-out of the wall can be observed at the location of the channels. It was also found that the distance from the surface of the cooling channel to the outer surface of the back of the lance should be 0.05 ÷ 0.50 of the wall thickness of the back of the lance at the location of the channel. With a lower value of the ratio, the coil quickly burns out due to being too close to the surface of the snout portion affected by the liquid metal, and with a larger ratio, the surface cooling drastically deteriorates.

It is possible to obtain an additional increase in the resistance of the tuyere due to increased cooling if the distance between the surfaces of adjacent channels in the direction of the tuyere axis is 0.01–0.60 of the length of the back of the tuyere. At a shorter distance, it is not possible to obtain a high-quality casting of the snout with such a small distance between the channels, and at a greater distance, cooling of the snout is reduced, which leads to a decrease in the resistance of the lance.

To form internal channels in the back of the tuyere, pipes or a square or rectangular section profile can be used.

The lance will have the greatest resistance, in which the flange, the outer and inner shells and the back part are connected by welds. Such a lance has great rigidity and tightness.

An example of a lance. The lance contains a pipe for supplying water, the outer and inner shells connected by welds with a flange and a snout. A coil in the form of a two-way spiral, which is connected to the pipe for supplying water, is poured into the copper snout portion, and a hole for water drainage leaves the snake snake coil directly into the rear chamber, which is limited by the outer and inner cases. Finally, water is discharged through a pipe in the flange. The inner diameter of the pipe coil in the snout is d = 30 mm, the wall thickness of the snout is S = 60 mm, the length of the snout is L = 275 mm. With a longitudinal axial section of the snout of the tuyere, 7 tubes fall into the plane of the section. In this case, the total cross-sectional area of the cooling channels with a longitudinal axial section of the snout of the tuyere with respect to the cross-sectional area of the wall of the snout of the tuyere will be:

The distance between the surfaces of two adjacent channels of the tube is: a = 7 mm, which is 0.026 of the length of the back of the lance.

The distance from the upper surface of the coil pipe to the outer surface of the snout of the lance is b = 20 mm, which is 0.33 of the wall thickness of the snout at the location of the cooling channel.

The technical and economic advantage of the proposed technical solution is to increase the durability of the tuyeres of the blast furnace, reduce the failure of the tuyeres, increase the stability of the blast furnace and increase the yield of metal.

Claims (5)

1. The tuyere of a blast furnace containing interconnected flange, the outer and inner bodies and the back part with cooling channels in the form of a coil, characterized in that the total cross-sectional area of the cooling channels with a longitudinal axial section of the back part of the tuyere is 0.07 ÷ 0.54 from the cross-sectional area of the wall of the back of the lance, and the distance from the inner surface of the cooling channel to the outer surface of the back of the lance is 0.05 ÷ 0.50 of the wall thickness of the back of the lance at the location of the channel. 2. The lance according to claim 1, characterized in that the distance between the inner surfaces of the adjacent cooling channels in the direction of the axis of the lance is 0.01 ÷ 0.60 of the length of the back of the lance. 3. A lance according to any one of claims 1 and 2, characterized in that the cooling channels form a flooded pipe. 4. A lance according to any one of claims 1 and 2, characterized in that the cooling channels form a flooded profile of square or rectangular cross-section. 5. The lance according to claim 1, characterized in that the flange, the outer and inner shells and the snout are interconnected by welds.

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