RU2779267C1 - Method for drying and heating of steel-posing ladder lining and device for its implementation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular to the heat treatment of steel-pouring ladles. In the method, the lining is heated by a burner and the working medium is removed by convective heat exchange outside the ladle. Laminar movement of the working medium is created in the cavity of the ladle due to the installation of a separating nozzle on the working surface of the lid, while the separating nozzle has a variable section, expanding towards the lid.

EFFECT: invention makes it possible to increase heat transfer from the working medium to the lining of the steel-pouring ladle, to reduce the emission of harmful gases into the workshop atmosphere, and also to increase the reliability and durability of the separating nozzle by reducing its heating temperature and increasing its thickness.

5 cl, 2 dwg.

Description

The invention relates to metallurgy, in particular to the heat treatment of steel-pouring ladles.

At present, the drying and heating of the lining of steel-pouring ladles at most metallurgical enterprises is carried out on special stands using gas-air burners.

The process of drying and warming up the lining of the ladle is reduced to heating the lining with heat, which is released in the process of converting some chemical compounds (fuel and oxidizer) into a mixture of other chemical compounds (combustion products, which are the working medium). Heat exchange occurs both by radiation and by direct contact of the working medium with the lining material, that is, by convection.

To maintain a high temperature of the working medium, the combustion process is constantly ensured, and the cooling working medium, already like smoke, is removed from the ladle space. In general, the process of drying and (or) heating is carried out with the help of moving materials that are in a gaseous state.

The movement of gases in the internal space of the ladle is a complex process as a result of the fact that, after the combustion of the fuel, the formed working medium, consisting of combustion products, is reflected from the bottom and walls of the ladle and rushes towards the torch into the smoke exhaust device. Therefore, the design of the smoke exhaust device plays an important role in determining the nature of the movement of the working environment.

Radiation plays a small role due to the low luminosity of the torch and the smoky interior of the ladle. The efficiency of convective heat transfer is largely determined by the nature of the movement (washing) of the lining surface by the working medium.

Known "Method of drying and heating a multilayer lining of a steel-pouring ladle" RU 2138365 [1], including installing the ladle on the stand, covering the ladle with a lid with a burner device fixed on it, supplying natural gas and air to the burner, igniting it, continuous heating of the lining with a torch, temperature which is regulated by the excess oxidizer coefficient, the removal of gaseous combustion products and moisture from the ladle, heating is carried out in three modes: drying mode, nominal mode and forced mode, while a multi-barrel ejector device is used as a burner device, the removal of combustion products and moisture is carried out through multi-barrel air ejectors, which are located in the lid evenly and symmetrically relative to the burner, and the lid is covered with a gap relative to the end of the ladle.

The disadvantage of this method is the low efficiency of heating the bottom of the bucket.

The closest to the claimed technical solution is the "Method of drying a monolithic lining of a metallurgical tank for liquid products and using a burner for this application" FR 2706991 [2], including the use of a lid with an installed gas burner installed with a gap between the lid and the upper part of the ladle, a separating nozzle cylindrical shape, located on the side of the cover facing the bucket.

The known device has an increased efficiency of heating the bottom of the ladle compared to [1] due to the presence of a separating nozzle that directs gases from the burner to the bottom of the ladle.

The disadvantages of the device include low reliability and durability due to overheating of a rather thin separating nozzle. The low efficiency is due to the turbulent nature of the flow of burner gases.

EFFECT: increased efficiency, reliability, durability. An additional technical result is the reduction of harmful emissions into the atmosphere of the workshop.

The technical result is achieved in that: the method of drying and heating the lining of a steel-pouring ladle covered with a lid with a burner and having a smoke exhaust device, including heating the lining with a burner and removing the working medium by convective heat exchange outside the ladle, is characterized by the fact that laminar movement of the working medium is created in the ladle cavity due to the installation of a separating nozzle on the working surface of the cover (which forms the flow of the working medium at the initial stage of combustion and at the final phase of the movement of the working medium).

The method may include a smoke exhaust device having a channel of increasing cross section from the periphery to the chimney (provides complete absorption of the removed smoke, without emissions into the environment).

A device for implementing the method according to claim 1, including a lid with an installed gas burner, a lid installed with a gap between the lid and the upper part of the ladle, a cylindrical separating nozzle located on the side of the lid facing the ladle, characterized in that the separating nozzle has a variable cross section expanding towards the lid.

The outer nozzle generatrix can be curved towards the center, and the inner nozzle generatrix can be inclined so that the channel section decreases towards the cover, which will further improve efficiency due to further reduction of turbulence.

The device may include an annular smoke box connected to the outside of the cover, which will further improve efficiency by increasing the temperature of the burner heads.

An annular smoke collector can be connected to a chimney nozzle, the annular smoke collector having a variable section, widest in the area of the chimney (least wide in the area opposite the chimney), which will further improve efficiency due to further reduction of turbulence.

Implementation of the invention:

In FIG. 1 shows a steel-pouring ladle (side view) installed on a device for drying and heating ladles, covered with an umbrella cover of the device, in Fig. 2 shows the same in section A-A, where:

1 - steel ladle with lining;

2 - cover;

3 - burner;

4 - torch;

5 - separating nozzle;

6 - chimney;

7 - smoke box;

8 - descending flow of gases of the torch;

9 - upward flow of gases of the working environment.

The device operates as follows:

The device for drying and warming up ladles works as follows: a steel-pouring ladle 1 with a lining that needs to be dried or heated is installed in a device for drying and warming up ladles. Cover (with umbrella) 2 covers the bucket with a gap, the value of which is determined by the technological process of drying and heating. Combustible gas and air are supplied to the burner 3, located along the ladle axis. The gas is ignited. The torch 4 coming out of the burner 3 is a certain volume of space filled with a substance in the gaseous state, in which physicochemical combustion reactions take place. The flow of gases that form the torch rests on the bottom of the ladle 1, is reflected from it and already as combustion products or a working medium that transfers heat to the lining of the ladle in a convective way, rushes towards the smoke exhaust device.

Due to the presence of a separating nozzle 5 in the cover, turbulences of the working medium are not formed in the space between the mouth of the burner and the surface, the conditions for the formation of a torch are improved, which further increases heat transfer. In addition, the separating nozzle allows you to form a uniform movement of the working medium into the smoke exhaust device.

When using a smoke box as part of a smoke exhaust device, the working medium, now just smoke, evenly leaves the bucket space through the gap between the umbrella cover and the edge of the bucket, while collecting in the smoke box channel 7. Naturally, the amount of smoke increases as the channel approaches from the far point to the chimney 6. Due to the increasing cross-section of the smoke box, the increasing amount of smoke freely goes into the chimney.

Thus, despite the fact that the processes of gas dynamics that take place in the internal space of the ladle, limited by the lid, are very complex, we can talk about the ordering of these processes, which will lead to a more complete heat transfer from the working medium to the lining of the steel-pouring ladle.

EFFECT: increased efficiency is achieved by increasing heat transfer from the working medium to the lining of the steel-pouring ladle. An increase in reliability and durability is achieved by reducing the temperature of the separation nozzle and increasing its thickness. The technical result is achieved by the fact that a profiled channel is installed on the inner surface of the cover at the mouth of the burner, separating the ignition zone of the burner torch from the zone of removal from the ladle of the working medium moving towards the torch, and the cross section of the channel contributes to the formation of a uniform outflow of the working medium from the ladle space without the occurrence of stagnant zones, due to which eliminates the turbulent movement of the working medium in the mouth of the burner, and ensures the direction of the flow of the working medium to the flue device, which has an increasing cross section, due to which all the smoke is placed in the channel, the volume of which increases from the periphery to the chimney.

Industrial applicability. The proposed method can be successfully used for heating steel-pouring ladles.

Claims (5)

1. A method for drying and heating the lining of a steel-pouring ladle covered with a lid with a burner and having a smoke exhaust device, including heating the lining with a burner and removing the working medium by convective heat transfer outside the ladle, characterized in that laminar movement of the working medium is created in the ladle cavity due to installation on the working surface of the separating nozzle cover, wherein the separating nozzle has a variable cross section, expanding towards the cover. 2. The method according to p. 1, characterized in that it includes a smoke exhaust device having a channel of increasing cross-section from the periphery to the chimney. 3. A device for implementing the method according to claim 1, including a lid with a gas burner installed, a lid installed with a gap between the lid and the upper part of the ladle, a separating nozzle located on the side of the lid facing the ladle, characterized in that the separating nozzle has a variable cross section expanding towards the lid. 4. The device according to claim 3, characterized in that the outer generatrix of the nozzle is curved towards the center, and the inner generatrix of the nozzle is inclined in such a way that the channel cross section decreases towards the cover. 5. The device according to claim 3, characterized in that the smoke exhaust device comprises an annular smoke collector connected to the outer side of the cover, the annular smoke collector is connected to the chimney branch pipe, and the annular smoke collector has a variable cross section, the widest in the chimney area.

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