KR101751527B1

KR101751527B1 - Appratus for heat insulation of sintering bed surface layer and this method

Info

Publication number: KR101751527B1
Application number: KR1020150182838A
Authority: KR
Inventors: 정철우
Original assignee: 주식회사 포스코
Priority date: 2015-12-21
Filing date: 2015-12-21
Publication date: 2017-06-27

Abstract

An ignition step in which the surface layer of the sintered bed is primarily heated above the sintering raw material layer; And a heat sink installed at a rear side of the ignition furnace to heat at least the surface layer portion of the sintered bed which has passed through the ignition furnace through at least radiant heat, and a heat keeping method for the sintered bed surface layer portion.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for heating a sintered bed,

A heat retaining device for a surface layer portion of a sintered bed and a heat retaining method for sintering the surface layer portion of the sintered bed.

Generally, sintered ignition types are divided into a reflective ignition furnace or a flameless ignition furnace. In the reflective ignition, the inner atmosphere temperature is maintained at 1100 to 1200 ° C. by ignition, and the binder (minute coke, anthracite, etc.) in the surface layer of the sintered bed is ignited. This method has the advantage of keeping the high temperature maintenance time of the surface layer long, although it is difficult to manage facilities by ignition and the amount of gas fuel is large.

On the other hand, in the flameless ignition, a flame of a gaseous fuel such as coke oven gas (COG) is directly brought into contact with the surface layer of the sintered bed to ignite the binder. Most sinter plants in recent years are using flame ignition furnaces to reduce gas fuel consumption.

That is, when the ignition type ignition furnace is used, it is possible to induce the surface layer ignition of the sintered bed using a small amount of fuel. However, after passing through the flame of the coke oven gas, the cold air from the outside is sucked through the sintered raw material layer, There is a drawback that the temperature is rapidly lowered.

For the production of high-quality, high-recovery sintered ores, the sintering raw material layer should be maintained at a temperature of 1200 ° C or higher for at least 150 seconds. If the high-temperature state can not be maintained sufficiently, calcium ferrite is not sufficiently produced and the firing strength is lowered.

In order to overcome the disadvantages of the ignition type ignition as described above, a tread band, which is formed of a heat insulating material at the rear end by flame ignition, is installed to heat the surface layer of the sintered bed. Further, in order to further enhance the insulating ability of the thermal insulation layer, a coke oven gas heat boiling furnace in which a gaseous fuel such as a coke oven gas is burned to maintain the atmospheric temperature inside the thermal insulation zone is also developed and used.

However, because the space for the inspection and repair of the sintering machine can absorb a large amount of outside air, the heat insulating efficiency is very low. The boiler furnace using the coke oven gas burner can maintain the internal temperature of the boiler over 600 ° C, but it has a disadvantage of consuming the coke oven gas.

In addition, since the amount of coke oven gas usable in the sintering plant is limited, if the COG is used in the boiler furnace, the flow rate of the coke oven gas which can be used in the furnace is reduced, Both sintering production and quality are adversely affected.

Provided is a superheat device for a superficial portion of a sintered bed and a method of superheating the sintered bed so that the radiant heat of the surface of the bed, which is absorbed into the troposphere or released into the atmosphere, can be recycled for the purpose of keeping the surface of the sintered bed warm.

The heat retaining device in the surface layer portion of the sintering bed is an ignition device for primarily heating the surface layer portion of the sintering bed at the upper portion of the sintering raw material layer; And a heat sink installed at a rear side of the ignition furnace to heat the surface layer portion of the sintered bed, which has passed through the ignition furnace, through at least radiant heat.

The tread band is provided in a structure at least partially covering the sintered bed surface layer portion.

The tread band is composed of a parabolic reflector having a curved structure reflecting the radiant heat of the surface layer of the sintered bed.

The parabola reflector is a structure formed by bending a stainless steel plate in a parabolic shape.

The parabola reflector may coat the glass surface on the reflecting surface that reflects the radiant heat.

The tread band may further include at least one fixing unit installed at an upper portion thereof to fix the tread band to the upper portion of the sintered bed surface layer.

A method for heating a surface layer of a sintered bed includes: a step of raising the temperature of a surface layer of a sintered bed primarily through ignition by providing an ignition furnace on a sintering raw material layer; And a parabolic reflector at the rear of the ignition furnace to insulate the surface layer of the sintered bed from the radial heat through the second heating step.

In the second heating step, the parabola reflector concentrates the heat reflected on the surface layer of the sintered bed at one point.

And the parabolic reflector is focused at a position where the temperature of the surface layer portion of the sintered bed starts to become 1200 ° C or less in the secondary heating step.

The surplus radiation heat generated in the first half of the parabolic reflector and the low utilization efficiency generated in the second half of the parabolic reflector can be concentrated at desired positions in the secondary heating step.

It is possible to secure a high-temperature holding time of 150 seconds or more by burning the binder in the surface layer portion of the sintered bed in the secondary heating step.

According to the present apparatus and method, sintering productivity and quality can be improved as the recovery rate is improved owing to the improvement of the sintering state of the surface layer of the sintered bed, and the surface ignition state is stabilized by the use of coke oven gas and stabilization of coke oven gas flow rate by ignition And securing the high-temperature holding time of the sintering raw material layer reduces the use of the binder and reduces the generation of carbon dioxide.

In addition, it is possible to increase the cooling efficiency of the sintered cooler and to manage the screen easily by reducing the generation of the surface layer unburned light, to reduce the sintering cost by suppressing the generation of scattering dust by the unexposed light and to reduce the fluctuation of blast furnace slag by the high quality sintering Can be saved.

1 is a view schematically showing a heat accumulating device of a surface layer portion of a sintering bed according to the present embodiment.
FIG. 2 is a graph showing temperature trends of the surface layer of the bobbin and the sintering bed according to the present embodiment.
3 is a graph showing the movement of electromagnetic waves in the parabolic surface of the parabola reflector according to the present embodiment.
Fig. 4 is a view schematically showing the configuration of the heat accumulating device in the surface layer portion of the sintering bed in this embodiment.
5 is a flowchart showing a process according to a method of heating the surface layer of the sintered bed in this embodiment.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified, and that other specific features, regions, integers, steps, operations, elements, components, and / And the like.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Accordingly, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

1 is a view schematically showing a heat accumulating device of a surface layer portion of a sintering bed according to the present embodiment.

FIG. 2 is a graph showing temperature trends of the surface layer of the bobbin and the sintering bed according to the present embodiment.

3 is a graph showing the movement of electromagnetic waves in the parabolic surface of the parabola reflector according to the present embodiment.

Fig. 4 is a view schematically showing the configuration of the heat accumulating device in the surface layer portion of the sintering bed in this embodiment.

As shown in Figs. 1 to 4, the heat accumulating device in the surface layer portion of the sintering bed is provided with an ignition furnace 10 (see Fig. 1) for heating the sintered bed surface layer portion 1 through the combustion of the coke oven gas, And a tamper bar 20 installed in a manner to cover the sintered bed surface layer portion 1 that has passed through the ignition furnace 10 from the rear side of the ignition furnace 10 and keep the sintered bed surface layer portion 1 warm through radiant heat .

The parabola reflector 21 is formed by bending a stainless steel plate in a parabolic shape so that the parabola reflector 21 is bent in a parabolic shape Structure.

The parabola reflector 21 may coat the glass film 21a on the reflecting surface that reflects the radiant heat.

Further, at least one trench 20 may be provided on the top of the trench 20 to fix the trench 20 to the upper surface of the sintered bed.

That is, in the heat retaining device of the sintered bed surface layer portion 1, the arborescent plate 20 composed of the parabolic reflector plate 21 is fixed to the upper portion of the sintered bed surface layer portion 1 by the fixing means 30, The parabola reflector 21 reflects the heat of the sintered bed surface layer portion 1 to raise the temperature so that the sintered bed surface layer portion 1 can be kept warm.

2, when the temperature of the parabolic reflector 21 and the surface layer of the sintered bed 1 are observed, the temperature of the surface layer is higher than that of the parabola reflector 21, So that the sintered bed surface layer portion 1 can be effectively kept warm by the parabola reflector 21.

As shown in FIG. 3, an electromagnetic wave such as light passes through the focus F when it is reflected from a parabola surface, so that energy can be concentrated. This principle can be applied to the interior of the sintering furnace as a heat source, so that the heat energy radiated from the sintering bed surface layer 1 can be recycled to the maximum extent.

Therefore, the parabola reflector 21 can be manufactured by bending a stainless steel plate in a parabolic shape, and then coating a glass film 21a on the reflection surface.

5 is a flowchart showing a process according to a method of heating the surface layer of the sintered bed in this embodiment.

As shown in Fig. 5, in the method for heating the surface layer of the sintered bed, an ignition furnace 10 is provided above the sintering raw material layer and the temperature of the sintered bed surface layer portion 1 is firstly raised through ignition of the ignition furnace 10 Step S1; And a parabolic reflector 21 on the rear side of the ignition furnace 10 so as to heat the sintered bed surface layer 1 by radiant heat through a second heating step S2.

In the secondary heating step S2, heat reflected by the parabola reflector 21 to the sintered bed surface layer portion 1 is concentrated at one point, and the temperature of the sintered bed surface layer portion 1 is 1200 ° C or lower So that the parabolic reflector 21 is focused.

Radiant heat generated in the first half of the parabola reflector 21 and radiant heat in the second half of the parabolic reflector 21 can be concentrated at desired positions in the secondary heating step S2, It is possible to secure a high-temperature holding time of 150 seconds or more.

That is, the temperature of the sintered bed surface layer 1 which passes through the coke oven gas flame of the ignition furnace 10 and is firstly ignited (heated) is lowered by suction of external air and radiant heat emission. The sintered raw material surface layer portion 1 is heated to the second position by focusing the parabola reflector 21 at a position where the internal temperature of the sintered bed starts to become 1200 캜 or less even after burning the binder due to the lowering of the surface layer temperature.

The parabola reflector 21 is advantageous in that the surplus radiation heat of the front half of the beam table 20 and the radiation heat of a lower utilization efficiency of the rear half can be concentrated at desired positions by using the reflection characteristic of the electromagnetic wave on the parabolic surface have.

Accordingly, it is possible to maintain the high-temperature holding time by burning the binder material on the sintering raw material layer for 150 seconds or more, thereby improving the recovery rate of the sintering raw material layer and reducing the generation of fine sintered ores. Since the accumulated heat energy is transferred from the middle of the sintering raw material layer, the sintering bed surface layer portion 1 may be cooled.

Therefore, sintering productivity and quality can be improved as the recovery rate is improved owing to the improvement of the sintering state of the sintered bed surface layer portion 1, and the surface ignition state can be improved by reducing the use of the coke oven gas and stabilizing the coke oven gas flow rate by ignition And securing the high-temperature holding time of the sintered raw material layer reduces the use of the binder and reduces the generation of carbon dioxide.

In addition, it is possible to increase the cooling efficiency of the sintered cooler and to manage the screen easily due to the decrease in occurrence of the surface layer microstructure, to reduce the sintering cost by suppressing the scattering dust generation by the microstructure and to reduce the fluctuation of blast furnace slag by the high quality sintering Can be saved.

While the illustrative embodiments of the present invention have been shown and described, various modifications and alternative embodiments may be made by those skilled in the art. Such variations and other embodiments will be considered and included in the appended claims, all without departing from the true spirit and scope of the invention.

1: Sintered bed surface layer 10:
20: beam tube 21: parabolic reflector
21a: glass film 30: fixing means

Claims

An ignition step in which the surface layer of the sintered bed is primarily heated above the sintering raw material layer; And
And a beam table installed at a rear side of the ignition furnace to heat the surface layer portion of the sintered bed that has passed through the ignition furnace through at least radiant heat,
Wherein the trench is provided in a structure that at least partially covers the surface layer portion of the sintered bed,
Wherein the tread band comprises a parabolic reflector having a curved structure reflecting the radiant heat of the surface layer portion of the sintered bed,
Wherein the parabola reflector is formed by bending a stainless steel plate in a parabolic shape.

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The method according to claim 1,
Wherein the parabola reflector coatings the glass surface on the reflective surface reflecting the radiant heat.

The method according to claim 1,
Further comprising fixing means installed at an upper portion of the treading table to fix the treading table to an upper portion of the sintering bed surface layer.

A step (S1) of raising the temperature of the surface layer of the sintered bed primarily through ignition by providing an ignition furnace on the sintering raw material layer; And
And a step (S2) of inserting a parabolic reflector plate at the rear side of the ignition furnace to heat the surface layer of the sintered bed through secondary heating by radiant heat,
In the secondary heating step S2, the heat reflected by the parabolic reflector to the surface layer of the sintered bed is concentrated at one point,
Wherein the radiant heat generated in the first half of the parabolic reflector in the second heating step (S2) and the radiant heat generated in the second half can be concentrated at a desired position.

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8. The method of claim 7,
Wherein the parabolic reflector is focused at a position where the temperature of the surface layer portion of the sintered bed starts to become 1200 DEG C or less in the secondary heating step (S2).

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8. The method of claim 7,
Wherein the high temperature holding time by the binder burning in the surface layer portion of the sintering bed in the secondary heating step (S2) can be secured for at least 150 seconds.