RU2397417C1 - Gas outlet of electric arc furnace - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: gas outlet consists of after-burning chamber, de-dusting chamber, cooled gas duct and receiving branch connected with after-burning chamber and equipped with movable driven clutch connected with roof branch of electric arc furnace at specified gap. Also the receiving branch is installed with incline to horizontal at 40-50° to a side of connection with the roof branch and has cross section area by 1.02-1.12 exceeding area of cross section of the roof branch.

EFFECT: reduced labour input at cleaning receiving branch.

1 dwg

Description

The invention relates to metallurgy and can be used in the designs of the exhaust duct of an electric arc furnace.

Closest to the claimed invention by the totality of the features is a gas outlet of an electric arc furnace selected as a prototype, comprising a post-combustion chamber, a dust deposition chamber and a cooled gas duct. A receiving branch pipe is connected to the afterburner, equipped with a movable coupling with a displacement drive for connecting it with a predetermined gap with the arch pipe of the electric arc furnace. The cooled dust deposition chamber is located under the afterburner and is equipped with a water-cooled gate, which provides access to the dust deposition chamber for periodic mechanized removal of dust and slag accumulated in the chamber from it. Behind the dust deposition chamber there is a water-cooled gas duct (Shvets M.N., Stalinsky D.V., Pirogov A.Yu. Capture and purification of dust and gas emissions from electric arc furnaces // Steel. - 2006. - No. 12. - P.72-74).

The object claimed as an invention and the prototype coincide with such essential features. Both devices contain an afterburner, a dust chamber, a cooled gas duct and a receiving nozzle connected to the afterburner and equipped with a movable drive clutch for connecting to a predetermined gap with the arc nozzle of the electric arc furnace.

Analysis of the technical properties of the prototype, due to its features, shows that the following reasons hinder the receipt of the expected technical result.

The operation of the design of the gas outlet of the electric arc furnace in the prototype is characterized by high complexity during cleaning of the receiving pipe, which connects the afterburner with the arch pipe of the electric arc furnace. This is due to the fact that slag metal discharges from the furnace remain on the cooled surface in the horizontal duct of the receiving pipe in the form of a layer of slag metal deposits with a thickness of 6-8 mm for each melt, and they are removed after the furnace is completed manually, causing an increase in the complexity of the removal process.

The basis of the claimed invention is the task of creating such a gas outlet of an electric arc furnace, in which improvements by changing the relative positions of the elements and the ratio of their parameters allows using the invention to achieve a technical result consisting in reducing the complexity of cleaning the receiving pipe connecting the afterburner with the arch pipe of the electric arc furnace.

The gas outlet of an electric arc furnace, claimed as an invention, contains a post-combustion chamber, a dust deposition chamber, a cooled gas duct and a receiving nozzle connected to the after-combustion chamber and equipped with a movable drive coupling for connecting with a predetermined gap to the arch pipe of the electric arc furnace. In this case, the receiving pipe is installed with an inclination to the horizontal of 40-50 ° in the direction of connection with the arch pipe of the electric arc furnace. Moreover, the receiving pipe is made with a cross-sectional area that is 1.02-1.12 times greater than the cross-sectional area of the arch pipe of the electric arc furnace.

When using the invention, the achievement of a technical result is achieved, consisting in reducing the complexity of cleaning the receiving pipe connecting the afterburner with the arch pipe of the electric arc furnace.

Between the totality of the essential features of the claimed invention and the achieved technical result there is the following causal relationship. The location of the receiving pipe with a slope of 40-50 ° horizontally in the direction of connection with the arch pipe of the electric arc furnace provides free sliding after each melting of frozen slag-metal deposits with a thickness of 6-8 mm from the cooled surface of the receiving pipe and their free removal through the technological gap between the movable drive coupling and arch pipe of an electric arc furnace. This technological gap between the movable drive clutch and the vault pipe of the electric arc furnace during the operation of the furnace is 40-100 mm, and after the end of the electric arc furnace - about 250 mm.

The implementation of the receiving pipe with a cross-sectional area greater than 1.02-1.12 times the cross-sectional area of the vault pipe of the electric arc furnace, ensures guaranteed reception of the total volume of gases that leave the vault pipe, taking into account the accumulation in the receiving pipe of all slag metal deposits in one melting.

The location of the receiving pipe with an inclination towards the connection with the arch pipe of the electric arc furnace of less than 40 ° is impractical, since such an angle will be smaller than the angle of repose, and will not guarantee free sliding of slag metal deposits on the inclined surface of the receiving pipe.

The location of the receiving pipe with an angle of inclination towards the connection with the arch pipe of the electric arc furnace greater than 50 ° is impractical, since the height of the afterburning chamber will increase, and accordingly its metal consumption and water consumption for cooling this chamber.

The implementation of the receiving pipe with a cross-sectional area exceeding the cross-sectional area of the arch pipe of the electric arc furnace by less than 1.02 times, is impractical due to the fact that this does not ensure the guaranteed reception of the entire volume of gases from the furnace arch pipe, taking into account the accumulation in the reception a branch pipe of a significant amount of slag metal deposits.

The implementation of the receiving pipe with a cross-sectional area exceeding more than 1.12 times the cross-sectional area of the arch pipe of the electric arc furnace is impractical, as this unreasonably increases its metal consumption and water consumption for cooling. In addition, with an increase in the cross section of the receiving pipe, the gas velocity in it decreases, which leads to an increase in the amount of slag metal deposits on its surface.

The essence of the claimed invention is illustrated by the drawing, which schematically shows a General view of the gas outlet of an electric arc furnace.

The drawing has the following notation:

1 - afterburner;

2 - dust deposition chamber;

3 - cooled gas duct;

4 - a receiving branch pipe;

5 - mobile drive clutch;

6 - arch pipe;

7 - electric arc furnace;

α is the angle of inclination of the receiving pipe.

In a specific exemplary embodiment, the gas outlet of the electric arc furnace comprises an afterburning chamber 1, a dust deposition chamber 2 and a cooled gas duct 3. A receiving nozzle 4 is connected to the afterburning chamber 1, equipped with a movable drive sleeve 5 for connecting to a predetermined gap with the arc nozzle 6 of the electric arc furnace 7. Receiving nozzle 4 installed with an angle of inclination to the horizontal of 45 ° in the direction of connection with the vault pipe 6 of the electric arc furnace 7, which in a specific embodiment is installed with the same angle of inclination to the horizontal as iemny pipe 4. This suction inlet 4 is formed with a cross sectional area greater than 1.1 times the cross sectional area of nozzle 6 arched arc furnace 7.

During melting, the electric arc furnace 7 is installed in a vertical position. The mobile drive clutch 5 by means of a drive is pushed towards the side of the pipe 6, while there is a gap of 40-100 mm to ensure the intake of air, which is necessary for the afterburning of carbon monoxide contained in the gases leaving the electric arc furnace 7. Furnace gases containing metal particles and slags in a liquid and plastic state, enter together with the air that is sucked through the gap into the receiving pipe 4. At the same time, some of the small particles of metal and slag solidify on the cooled surface of the receiving pipe and 4 in the form of a crust of slag metal deposits with a thickness of 6-8 mm. Next, from the receiving pipe, the gas-air mixture enters the afterburning chamber 1, where carbon monoxide is burned. From the afterburning chamber 1, the gases enter the dust deposition chamber 2, where particles of metal and slag are deposited and the gases are cooled. Further cooling of the gases and their entry into the gas purification system (not shown in the drawing) is carried out through a cooled gas duct 3.

After melting, the flow of hot gases from the electric arc furnace 4 through the arch pipe 6 stops. The mobile drive clutch 5 is diverted from the arched nozzle 6. Into the receiving nozzle 4, due to the vacuum created by the gas cleaning system (not shown), cold air is sucked in. Slag metal crust due to cooling by the suction air and heat transfer to the cooled wall of the receiving pipe 4 very quickly hardens. In this case, the slag metal crust under the influence of thermal stress is compressed, cracked, separated from the surface of the receiving pipe 4 and slides along its inclined surface towards the vault pipe 6. Once in the gap between the vault pipe 6 and the movable drive sleeve 5, the cinder metal cake is slowly effortlessly removed from receiving pipe 4. In this case, the need for manual cleaning of the receiving pipe 4 disappears.

Claims (1)

An electric arc furnace gas outlet containing an afterburner, a dust deposition chamber, a chimney flue and a receiving nozzle connected to the afterburner and equipped with a movable drive coupling for connecting to the arc nozzle with a specified clearance, characterized in that the receiving nozzle is installed with an inclination to the horizontal of 40- 50 ° towards the connection with the arch pipe of the electric arc furnace, while the cross-sectional area of the receiving pipe is 1.02-1.12 times greater than the cross-sectional area mentioned th arched branch pipe.

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