KR101330275B1 - Outside air inflow prevention device for reheating furnace - Google Patents

Abstract

The present invention relates to an external air intrusion prevention apparatus for a furnace that can block external air inflow and internal air discharge when extracting the slab heated to an appropriate temperature in the furnace, the characteristic configuration of the charge opening on one side ( 101 is formed, the heating furnace 100 is provided with a door 120 for selectively opening and closing the charging port 101; An auxiliary door 150 rotatably installed around the hinge 151 installed at the lower end of the door 120; A support member 160 installed to be inclined upward toward the charging hole 101 so that the auxiliary door 150 rotates forward of the charging hole 101 when the auxiliary door 150 is lowered; And a stopper 152 installed at the lower end of the door 120 to limit the amount of rotation of the auxiliary door 150 by the end of the rotating auxiliary door 150. Including, but the amount of the outside air introduced through the charge 101 is reduced, characterized in that the lower portion of the charge 101 and the door 120 is formed so that the flow of the discharged gas is changed.

Furnace, Slab, Flue Gas, Extraction

Description

Outside air inflow prevention device for reheating furnace

1 is a cross-sectional view showing a general heating furnace.

Figure 2 is a graph showing the oxygen concentration due to the outside air introduced into the furnace.

Figure 3 is a perspective view showing a conventional external air diffusion prevention structure.

Figure 4 is a cross-sectional view showing an external air intrusion prevention apparatus according to the present invention.

Figure 5 is a cross-sectional view of the external air intrusion prevention apparatus according to the present invention opened.

Figure 6 is an enlarged cross-sectional view of the main portion of the external air intrusion prevention apparatus according to the present invention.

7 to 11 are cross-sectional views showing a process of extracting the slab in the heating furnace in which the external air intrusion prevention apparatus according to the present invention is installed.

[Description of Reference Numerals]

S: slab

100: heating furnace

101: charging

110: Table

120: Door

130: motor

131: wire

150: auxiliary door

152: Stopper

160: support member

The present invention relates to a device for preventing intrusion of external air for a furnace, and more particularly, to prevent external air ingress for a furnace that can block inflow of external air and discharge of internal air when extracting a slab heated to an appropriate temperature in a furnace. Relates to a device.

In general, in order to roll the slabs produced in the machine, the slabs are heated to a rolling temperature inside the heating furnace, and the heated slabs are extracted to the outside of the heating furnace using an extractor.

The inside of the furnace for heating the slab generates a high temperature oxidation scale generated on the surface of the heating material by securing a heating temperature and forming an oxidizing atmosphere, and realizes complete combustion of the fuel and at the same time generates NOx generated during combustion due to excess oxygen. In order to minimize the amount of production, the external air flowing into the furnace should be blocked when the slab is extracted.

In the case of supplying heat through combustion of fuel to heat the slab in the furnace, air for reaction of C and H in the fuel, that is, oxygen, is required, and for this, it is usually reacted by supply of fuel and air through a burner Will be generated.

At this time, the amount of oxygen supplied during combustion (air amount, referred to as the amount of oxygen below) is slightly more than the amount of oxygen for the complete combustion of the fuel, which is to ensure complete combustion during the combustion reaction, which is thermal efficiency due to excess oxygen The purpose is to prevent the degradation of NOx and the excessive generation of NOx produced during the combustion reaction.

In addition, in some cases, the amount of excess oxygen is increased when forming an oxidizing atmosphere for forming the scale so that the high temperature oxidation scale generated on the surface of the heating material easily falls off from the surface of the heating material during rolling.

In order to control the amount of excess oxygen according to the purpose of use, for the purpose of setting the excess oxygen amount based on the calorific value of the fuel used in the furnace, the component of the fuel used is instantaneously analyzed to supply the required amount of oxygen, or among the components of the exhaust gas generated after combustion. The method of determining and supplying the amount of oxygen to be supplied continuously by measuring the oxygen concentration is applied.

Controlling the appropriate amount of excess oxygen is important in terms of thermal efficiency and scale generation mentioned above. The most sensitive reaction of these effects is the NOx generated during combustion, and the amount of NOx generated has a positive correlation with the excess oxygen concentration.

In particular, the excess oxygen amount is the post-combustion reaction when the corresponding conditions are matched not only in the reaction stage during combustion but also in the flow of the combustion gas after combustion, resulting in an increase in the final NOx generation amount due to the additional NOx generation amount.

In recent years, in addition to the management of CO2 emissions, legislation to manage and regulate the generation or concentration of NOx has been promoted. The management and control of a small amount of excess acid is required.

However, the company has applied its own management methods and devices for such matters, but excess oxygen is introduced into the furnace regardless of the actual combustion.

In this case, the air is introduced from outside by the opening and closing of the door during charging and extraction after heating and heating the heating material in the heating furnace. Although loss occurs, inflow of external air occurs even if the pressure condition of the furnace is kept higher than atmospheric pressure to prevent the inflow of atmospheric air from the outside.

In the case of the intrusion air generated when the door of the heating furnace is actually opened, the hot exhaust gas of the heating furnace is discharged to the atmosphere in the upper layer of the door, and the phenomenon of the inflow of atmospheric air in the lower layer of the door occurs.

This phenomenon is slightly different depending on the heat load of the combustion zone adjacent to the door of the furnace, that is, the amount of exhaust gas generated, but basically it is released into the atmosphere when hot gas in an enclosed space is opened and closed. This is due to diffusion and pressure gradient to make up for the space of the hot gas.

Therefore, the discharge of hot gas and infiltration of atmospheric air basically occur all the time when the heating door is opened and closed. In this aspect, the outside of the cold air, which has invaded the air, that is, into the heating furnace of the air containing 21% of oxygen concentration Has been seeking ways to prevent the spread of

Hereinafter, with reference to the accompanying drawings showing a conventional heating furnace will be described.

As referred to herein, a table 110 for supporting the slab S is installed inside the heating furnace 100, and a charging hole 101 is formed at one side of the heating furnace 100. The door 120 is installed at the charging hole 101.

A motor 130 is installed on an upper surface of the heating furnace 100, and a wire 131 is connected between the motor 130 and the door 120.

In addition, an extractor 140 for charging or extracting the slab S into or into the outside of the heating furnace 100 is installed outside the heating furnace 100.

Therefore, when the motor 130 installed on the upper surface of the heating furnace 100 is operated in the forward direction, the wire 131 is pulled, and when the wire 131 is pulled, the door 120 connected to the wire 131 is pulled out. Move to the top, the charging hole 101 is to be opened.

When the charging inlet 101 is opened as described above, the slab S is charged into the table 110 installed in the heating furnace 100 using the extractor 140, or heated in the heating furnace 100. Completed slab (S) is extracted.

However, in the conventional heating furnace 100, as shown in FIG. 1, a large amount of air is introduced into the heating furnace 100 at the same time as a large amount of external air is introduced through the charging opening 101 which is opened by the door 120. Is discharged to the outside.

Due to the inflow of external air, there is a problem in that the oxygen concentration increases inside the heating furnace 100 as shown in FIG. 2.

As shown in FIG. 3, a damper 102 is installed inside the heating furnace 100 to prevent external air introduced into the heating furnace 100 from being diffused in the heating furnace 100. However, at this time, the combustion gas flow in the heating furnace 100 has a limit as a countermeasure against external air invading due to the difference in the amount of exhaust gas generated according to the heat load of the heating furnace 100.

The present invention has been invented to solve the above problems, the object of which is to naturally occur by changing the flow of hot exhaust gas discharged to the outside at the same time blocking the path of external air invading through the charging opening when opening the door It is to provide an external air intrusion prevention device for a furnace that can prevent the decrease in the thermal efficiency due to the increase in oxygen concentration inside the furnace and the cold air inlet by suppressing the inflow of external air.

In order to accomplish the above object, a characteristic configuration of the present invention will be described as follows.

External air intrusion prevention device for a heating furnace of the present invention is a charging inlet 101 is formed on one side, the heating furnace 100 is provided with a door 120 for selectively opening and closing the charging inlet 101; 120) the auxiliary door 150 rotatably installed around the hinge 151 installed at the lower end; A support member 160 installed to be inclined upward toward the charging hole 101 so that the auxiliary door 150 rotates forward of the charging hole 101 when the auxiliary door 150 is lowered; And a stopper 152 installed at the lower end of the door 120 to limit the amount of rotation of the auxiliary door 150 by the end of the rotating auxiliary door 150. Including, The amount of outside air introduced through the charge 101 is reduced, characterized in that the lower portion of the charge 101 and the door 120 is formed so that the flow of the discharged gas is changed.

The present invention having such characteristics will be described in detail as follows.

Figure 4 is a cross-sectional view showing an external air intrusion prevention apparatus according to the present invention.

As referred to herein, a table 110 for supporting the slab S is installed inside the heating furnace 100, and a charging hole 101 is formed at one side of the heating furnace 100. The door 120 is installed at the charging hole 101.

On the other hand, the auxiliary door 150 is rotatably installed around the hinge 151 in the lower portion of the door 120, the stopper 152 to limit the amount of movement of the auxiliary door 150 in the door 120. Is installed.

In addition, a support member 160 for rotating the auxiliary door 150 is installed below the charging hole 101.

In addition, a motor 130 is installed on an upper surface of the heating furnace 100, and a wire 131 is connected between the motor 130 and the door 120.

In addition, an extractor 140 for charging or extracting the slab S into or into the outside of the heating furnace 100 is installed outside the heating furnace 100.

Therefore, when heating the slab (S) is to move the door 120 to the bottom to block the charging opening 101 of the heating furnace 100, in this case the auxiliary door 150 installed in the lower portion of the door 120 Since the state in contact with the support member 160, the lower end is maintained to be rotated to face upward.

On the other hand, when charging the slab (S) in the interior of the heating furnace 100, or extract the heated slab (S) is to operate the motor 130 installed on the upper surface of the heating furnace 100, the motor When the 130 is operated, the wire 131 is pulled, and when the wire 131 is pulled, when the door 120 connected to the wire 131 moves upward, the charging hole 101 is opened.

When the door 120 moves upward as described above, the auxiliary door 150 installed at the bottom of the door 120 is rotated about the hinge 151 by its own weight, and the door 120 is completely opened. In this case, as shown in FIG. 5, the auxiliary door 150 is restricted by rotation by the stopper 152 to maintain the inclination angle.

Therefore, the hot exhaust gas in the heating furnace 100 discharged to the outside is directed to the lower portion of the open door 120 and the auxiliary door 150.

That is, according to the present invention, since the flow and flow rate of the hot exhaust gas in the heating furnace 100 discharged to the outside through the open charging hole 101 are changed as shown in FIG. In response, the intrusion of external air is reduced.

In addition, since the lower part of the charging hole 101 and the door 120 is curved as shown in FIG. 6, a Coanda effect (fluid) in which hot gas flows out through a curved surface is curved. Fluidity in the lower part is improved by the tendency to adsorb to the surface when the surface flows.

On the other hand, it will be described with reference to the accompanying drawings showing the process of drawing out the heated slab (S) as shown in Figs.

First, when heating the slab (S) as shown in Figure 7 the door 120 is moved to the bottom to block the charging port 101.

When the heated slab (S) is extracted, the door 120 is moved upward, and the auxiliary door 150 is separated from the support member 160 to rotate about the hinge 151 and the auxiliary door. As shown in FIG. 8, the inclination angle is maintained so that the exhaust gas therein is discharged to the lower portion of the door 120.

At this time, the extractor 140 is inserted into the furnace 100 to extract the heated slab S, and when the slab S is extracted, the auxiliary door 150 is the slab as shown in FIG. 10. Since it is rotated by (S) it is prevented that the exhaust gas is discharged to the upper slab (S).

On the other hand, when the slab (S) is completely extracted, as shown in Figure 11, the auxiliary door 150 is rotated by its own weight, thereby minimizing the inflow of outside air and the amount of exhaust gas discharged.

In addition, when the door 120 is moved downward, the auxiliary door 150 is rotated by the support member 160 as shown in FIG.

As described above, the present invention can minimize external air invading through the charging inlet of the heating furnace and exhaust gas discharged to the outside at every moment of opening the door when charging and extracting the slab. Has a unique effect of reducing the overall thermal efficiency of the furnace, the reduction of the operation control of the furnace due to the increase of the oxygen concentration in the furnace, the increase in the generation of high temperature scale and the generation of NOx, a pollutant.

Claims (3)

A heating furnace (100) formed at one side thereof and having a door (120) for selectively opening and closing the charging hole (101); An auxiliary door 150 rotatably installed around the hinge 151 installed at the lower end of the door 120; A support member 160 installed to be inclined upward toward the charging hole 101 so that the auxiliary door 150 rotates forward of the charging hole 101 when the auxiliary door 150 is lowered; And A stopper 152 installed at a lower end of the door 120 to limit an amount of rotation of the auxiliary door 150 by an end of the rotating auxiliary door 150; , ≪ / RTI & The amount of outside air introduced through the charging inlet 101 is reduced, and the lower portion of the charging inlet 101 and the door 120 is formed so that the flow of the discharged gas is changed, the outside of the furnace Air Intrusion Prevention Device. delete delete

Images