SU1043168A1 - Blast furnace air heater - Google Patents

Abstract

DOMAIN FURNACE AIR HEATER, containing combustion chambers and nozzles, separating. a wall with a Compensation layer and a cavity in the gap between the layers of the refractory lining formed by two metal sheets, They are made across the entire width of the gap, from the fact that, in order to increase the resistance of the dividing wall, the cavity is sealed in the form of a shell made of metal sheets fastened around the perimeter of the shell, between which a metal partition is installed, not reaching the top of the shell for a distance equal to 0.8-1.0 of the width of the shell, with a compressed air supply nozzle attached to the cavity on the side of the chamber, and an outlet of compressed air to the cavity on the side of the nozzle chamber. air ..: 4 u: Y X

Description

The invention relates to ferrous metallurgy, in particular, to designs of air heaters for blast furnaces, and can be used in all branches of the public household, where high-temperature heating of gases is not required.

Domain blast stoves with a built-in combustion chamber, containing combustion chambers and nozzles, as well as a dividing wall with a screen of heat-resistant steel fj are known.

: The disadvantage of these stoves is the low resistance of the separating wall of the combustion chambers and the nozzle. .

Closest to the proposed solution for. The technical essence and the achieved economic effect is a blast furnace air heater containing combustion chambers and nozzles, a dividing wall with a compensation layer and a cavity in the gap between the layers of refractory lining formed by two metal sheets installed over the entire width of the gap 2

A disadvantage of the known construction of a blast furnace air heater is the following.

During the period of blowing into the cavity of the separation wall, a part of the cold blowing is supplied, which heats up in it / and then mixes in the upper part of the combustion chamber with hot blowing. Therefore, the upper part of the combustion chamber during the blowing period plays the role of a blast furnace mixer. .

The hot blast coming out of the nozzle, and at the initial-moment of the period, the temperature is higher than the final one, by 10.0-150 ° С. In order to maintain a constant temperature of the blow supplied to the furnace, it is necessary during this period to reduce the flow rate of the blown heated in the cavity, - To values acceptable for the durability of metal sheets. This leads to a change in the temperature of the metal over time and a decrease in the reliability of the separation wall.

In addition, to maintain the durability of metal sheets of the cavity, it is necessary to continuously supply compressed air into it. Therefore, when translating air heaters from periods to blow on heating and from heating on. blowing (6–12 min per operation) heated air is not used and is emitted into the atmosphere.

The aim of the invention is to provide a predetermined temperature under the dome-air heater heated by low-calorie fuel, and to increase the reliability of the separation wall.

The goal is achieved by the fact that in the air heater of the blast furnace, containing combustion chambers and nozzles, a dividing wall with a compensation layer and a cavity

 in the gap between the layers of the refractory lining formed by two metal sheets installed across the entire width of the gap, the cavity is sealed in the form of a shell of metal sheets fastened around the perimeter of the shell, inter-. . which is installed metal-. ka partition, not reaching the top of the shell for a distance of 0.8-1.0 shell width, with a nozzle for compressed air supply on the side of the combustion chamber, and a branch pipe for the nozzle chamber on the cavity compressed air.

FIG. 1 shows an air heater, vertical section; in fig. 2. - the same, horizontal raz5 res; in fig. 3 - metallic cavity, vertical section, in FIG. 4 - the same horizontal cut. .

The blast furnace air heater consists of a metal casing 1, to the inner surface of which there is a refractory masonry 2 adjacent. The air heater contains cam 3 nozzles and an integrated combustion chamber 4, united by a common dome

5 5. In the burning chamber 4, the fittings 6 are hot and blown. burner 7. The chamber 3 is mounted on the chamber 4, a multilayer separating wall 8, consisting of

0 layers 9 and 10 of the refractory masonry, compensation layers 11, an air-cooled cavity 12, inside of which a metal partition 13 is formed over its entire width, forming two cavities 14 and 15. The cavities 14 and 15 at the top communicate with each other by a slit 16, and height equal to 0.8-1.0. shell width. The shell 14, adjacent to the combustion chamber 4, is connected to the compressed air supply pipe 17, and the cavity 15 adjacent to the tank 3, to the heated air outlet pipe 18 and the burner 7 fitting, inside the cavities 14 and 15 to the full their thickness is determined by the ribs-turbulizers 19, arranged in a checkerboard pattern.

Air blast furnace works as follows. During the period of heating gas-air.

0, the mixture is fed through the burner 7. Combustion products formed during the combustion of the fuel in the combustion chamber 4 pass into the nozzle 3, where they give their heat to the wall, and leave the heater. Temperatures

The height of the combustion chamber differs slightly from the temperature under the dome (by 50-80 ° C),

During the period of blowing, the cold air is supplied to the lower part of the nozzle 3, heated in it and through the nozzle 6 enters the direct and annular air duct and into the furnace.

Compressed air is constantly used during all periods of operation of the stove through the pipe 17 into the cavity 14 adjacent to the 4-combustion chamber. Then the air passes upward through the web 14, gets into the slot 16, and the passage down the cavity 15 adjacent to the nozzle 3 comes out through the nozzle 18 into the common manifold, and then it is distributed to the burners of the air heaters. Compressed air, passage along the cavity m. 14 and 15, cools to the fret of dividing wall 8 and heats up to 400-500 C. To prevent the cavities from splitting 14 and 15., compensation mats 11, for example, of type ICRB-50, which can operate at temperatures up to: (GOST 20901- 75). Inside the cavities 14 and 15, stiffening ribs 19 are installed in a staggered order, which turbulent the air flow and increase heat transfer from the walls to (Heated air). In the proposed design, the compressed air supplied to the shells of the dividing wall flows continuously and its consumption does not depend from the heating and blowing periods. In a known air heater in, the cavity must be continuously supplied with cold blowing or during the period of boil: roaring-compressed air with a pressure exceeding the pressure in the working space of the combustion chamber by 10-20%, and during the blow - cold blast ..

It is known that the cost of air heaters with a remote combustion chamber is 20-30% more than with a built-in one, and that more space is needed for their construction, so that not all of them are possible. to change.

In the proposed construction, during the pauses (transfer of air heaters from one mode to another), the air heated in the shells is not emitted into the atmosphere, but is used to burn low-calorie fuel.

The need to choose the accepted design parameters of the dividing wall is as follows.

The height of the gap between the metal partition and the upper horizontal sheet of the cavity is chosen from the conditions of equality of velocities in it and both cavities. This condition is feasible if their areas are equal. If the cross-sectional area for the passage of air is filled with turbulence ribs, the height of the slit should be 0.8-1.0 of the shell thickness. When the height of the slot decreases, the speeds of air movement and pressure loss will increase and the target may flatten. If turbulum ribs are not used in the cavity, the height of the slot is equal to the thickness of the shell. If the gap height is greater than the shell thickness, then the velocity of air in it is less, the heat transfer from the horizontal sheet of the cavity to the air will decrease, which will reduce the resistance of the metal sheet. The supply of cold air to the vileness adjacent to the combustion chamber, and the discharge of unheated air through the cavity adjacent to the nozzle is due to the fact that the temperature in the combustion chamber is greater than in the nozzle, which ensures great efficiency.

The invention saves natural or coke oven gas and increases the reliability of the separation wall;

The implementation of the invention in relation to a blast furnace with an annual output of 1 million tons of pig iron, as compared with the known air heater design, saves 1200-2000 m of natural gas and improves the reliability and durability of the combustion chamber by 10-20%. The economic effect is 259.8 thousand rubles. in year.

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Claims (1)

BLAST FURNACE AIR HEATER, containing combustion chambers and nozzles, separation. a wall with a compensation layer and a cavity in the gap between the layers of the refractory lining formed by two metal sheets, mounted over the entire width of the gap, characterized in that, in order to increase the resistance of the separation wall, the cavity is sealed in the form of a shell of metal sheets fastened around the perimeter by a shell, between which a metal partition is installed, not reaching the top of the shell by a distance equal to 0 , 8-1.0 the width of the shell, and from the side of the combustion chamber to the cavity is attached a nozzle for supplying compressed air, and from the side of the chamber of the nozzle to the cavity is attached a branch pipe for compressed air. air. . ·. 4 * fo