JPH04123242U - Heating furnace with excellent sealing properties for the slag hole - Google Patents

Abstract

(57) [Summary] [Purpose] The present invention is a heating furnace that can prevent air from entering through the slag discharge hole duct of the furnace for discharging molten scale. This improves the furnace temperature control, atmospheric gas control, and furnace pressure control functions, and improves the quality of heated materials and saves energy. [Structure] A water curtain sealing device that blows out from the surrounding area is installed and sealed in the slag hole duct that removes molten scale to prevent air from entering from outside the furnace.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a system for a slag exhaust hole duct in a heating furnace that facilitates the discharge of molten scale during operation. It is about the rules.

0002

[Conventional technology]

In a continuous heating furnace, molten scale that forms on the surface of the heated object falls and burns in the furnace. It may accumulate on the floor surface and erode the hearth refractories, or it may accumulate on the hearth and cause combustion in the lower zone burner. It may disturb the firing state and significantly reduce the combustion efficiency, or it may disturb the burning condition and significantly reduce the combustion efficiency. It may enter the opening in the hearth provided for the purpose of heating, obstructing the conveyance of the heated material, and preventing smooth operation. often hinders In other words, in a continuous heating furnace, the steel billet to be heated is heated to a predetermined target temperature suitable for rolling. It is also important to discharge the melted scale out of the furnace.

0003 If this molten scale accumulates on the hearth, it will cause various problems, so avoid accumulating it as much as possible. Measures have been taken to ensure that the waste is discharged outside the furnace. For example, Special Publication No. 49-3884 In this report, the center of the hearth in the hearth width direction is high and both sides are low, and scales are placed on both sides of this low height. A slag drainage groove is provided, and the scale sludge drainage groove is connected to an inclined slag removal groove provided outside the furnace. An injection nozzle that turns scale into slag and a water supply device for slag are installed near the end of the diagonal slag drainage groove. ing. This makes it easy to remove scale from the furnace.

0004

[Problem that the idea aims to solve]

By the way, the slag drainage hole duct that connects the scale slag drainage groove provided in the hearth and the slag drainage groove outside the furnace. Although a sealing device using a plug-in damper is installed at the site, melted scale is generated. In high-temperature operations where slag is produced, the damper is left open to ensure smooth slag drainage, and the slag drainage hole duct is closed. The lower part of the pipe is not completely sealed with water and is dropped into the water flowing through the slag formation duct to form water slag. are doing. The reason for this is that if the bottom of the slag drainage hole duct is completely water-sealed, this High-temperature molten scale that fell from the slag drainage hole duct enters the water, causing the water to expand rapidly. This is because it is dangerous because it can explode if stretched.

[0005] Therefore, a large amount of air enters the furnace from outside the furnace through this slag exhaust hole duct. This increases the oxygen concentration in the furnace and contributes to the promotion of molten scale. Ta. In addition, cold air entering the furnace will cause the atmospheric temperature inside the furnace to drop. In order to raise the temperature inside the furnace, it is necessary to input more fuel, which increases fuel costs. It was also getting worse.

[0006] In addition, in order to reduce the amount of air entering from the slag drainage hole duct at the bottom of the hearth. It may be possible to set the pressure in the furnace to a higher level in order to The high-temperature exhaust gas inside the furnace flows through the opening of the peephole, which is located high in the direction and has high pressure inside the furnace. It may blow out and cause the steel shell on the furnace side to become red-hot and damage it, or high-temperature exhaust gas may blow out of the furnace. There is a strong possibility that this will have an adverse effect on fuel costs and safety. In addition, it is possible to heat objects that do not require high-temperature heating, e.g. When heating at a temperature of I inserted the plug-in damper in the middle part, but the seal around the damper was not good. It is not perfect, and air can enter through this gap.

[0007] Oxygen in the air that enters the furnace reacts with the heated steel pieces, generating a large amount of scale. This results in a decrease in yield and also causes defects in terms of quality. Further invasion The amount of fuel used also increased due to the influence of incoming air. This invention completely prevents air from entering, and prevents air from entering from the slag hole duct. The purpose of the present invention is to provide a sealing device for a slag hole duct that does not cause any problems caused by such problems.

[0008]

[Means to solve the problem]

The gist of this invention is that the scale drainage groove is installed at the bottom of the hearth of the heating furnace and the A water curtain sealing device was installed on the slag drainage hole duct that connects the slag removal duct. The heating furnace is characterized by an excellent sealing property of the slag discharge hole. According to this invention, slag removal The hole duct is always water sealed, and this sealing effect controls the temperature inside the furnace. control, atmospheric gas control, and furnace pressure control, as well as suppressing scale generation and reducing combustion. It is possible to reduce the amount of materials used and prevent the occurrence of defects.

[0009] Next, the present invention will be described in detail based on one embodiment with reference to the drawings. FIG. 1 is a sectional view of a continuous heating furnace. The object to be heated, for example, steel piece 1 is the main skid. 2 and support skid 3, and is heated while being conveyed. The scale melted from the surface of the steel slab 1 heated to a high temperature falls onto the hearth 10. The flow transitions to scale scavenging grooves 4 on both sides, which are lower in the width direction of the furnace.

0010 In this case, in order to prevent solidification of the molten scale that has fallen onto the hearth 10 and to promote fluidity, It is heated by combustion using a slag melting burner 5. 6 is a water slag duct installed outside the furnace, which turns the melted scale into water slag and drains it out. It is. 7 is a slag drainage hole duct, which connects the scale slag drainage groove 4 and the slag formation duct 6. The molten scale that has come to the top of the slag hole duct 7 drains water through this. The water flows down into the flowing water slag forming duct 6 and is turned into water slag.

[0011] 8 is a water curtain sealing device, which is installed in the slag hole duct 7 and The water curtain sealing device 8 is connected to a water supply source (not shown) and It is blown out toward the inside of the slag discharge hole duct 7 to seal it. As a result, the melt hole duct 7 For example, air entering from the lower gap between the It is completely sealed with a water curtain seal 9 from a water filter device 8.

0012 Although this example was explained using a walking beam type, it is not possible to use a pusher type. It can be carried out in the same way even if the heating furnace is a continuous heating furnace or a batch heating furnace. The same thing.

[0013]

[Effect of the idea]

With this invention, the slag hole duct is used to discharge molten scale that has fallen onto the hearth of the heating furnace. The oxygen concentration inside the furnace is reduced because the air entering from the furnace is eliminated or greatly reduced. , the amount of melted scale generated is also reduced. In addition, the amount of scale generated and the occurrence of scratches during high-temperature operation are It also reduces the amount of raw material. Furthermore, by reducing the amount of intruding air, the drop in temperature inside the furnace is also reduced, reducing fuel usage. The amount can also be reduced. In addition, since there is less air entering, there is no need to raise the furnace pressure extremely, and the iron shell Damage is also reduced, leading to lower repair costs.

[Brief explanation of drawings]

Figure 1 is a diagram showing a side cross section of a heating furnace in an embodiment of the present invention, Figure 2 is a diagram showing a vertical cross section of a heating furnace in an embodiment of the invention, and Figure 3 is an exhaust diagram in an embodiment of the invention. Diagram showing the seal of the slag hole duct,

[Explanation of symbols]

1: Steel piece, 2: Main skid, 3: Support skid, 4: Scale drainage groove, 5: Slag melting burner,
6: Water slag formation duct, 7: Slag drainage hole duct, 8: Water curtain seal device, 9: Water curtain seal, 10: Hearth.

──────────────────────────────────────────────── ─── Continuation of front page (72) Creator Yutaka Soejima 1-1 Hibata-cho, Tobata-ku, Kitakyushu, Fukuoka Prefecture Shin Nippon Steel Corporation Yawata Works

Claims (1)

[Scope of utility model registration request] [Claim 1] A slag drainage system characterized in that a water curtain sealing device is provided in a slag hole duct that connects a scale slag groove provided in the hearth of a heating furnace and a slag formation duct provided outside the furnace. A heating furnace with excellent hole sealing properties.