JPS59179705A - Method of protecting blast furnace bottom - Google Patents

Abstract

PURPOSE:To protect the refractories in the bottom of a blast furnace and to extend the life thereof by forming the molten iron or slag deposits to be generated as a result of cooling on the surface of the lower peripheral wall in the furnace bottom and well which is in contact with a molten metal. CONSTITUTION:A block 1 provided with a hole 4 is used for the uppermost stage of the bedding of a carbon block 1 for the furnace bottom. A cooling gas pipe 3 is installed in the hole 4 and a nozzle 3b is provided thereto. The nozzle 3b is formed by combining an outside pipe 9 with an inside pipe 8 apart at a slight space therefrom and inserting the pipe into the hole 4 by using mortar 10, etc. Blowing of cooling gas through the nozzle 3 is started when a molten iron is produced after firing. When the rate of tapping begins to increase, the wear of the clay brick on the working surface side progresses and the brick is disloged. The molten metal around the nozzle 3b is thereafter cooled by the effect of the cooling gas and the deposit of the molten iron initiated by the working surface of the pipe 9 and the mortar 10 begins to be produced. The abrasion and accumulation in the deposit are balanced at certain thickness at the temp. and by the movement of the molten iron until finally the protective wall enclosing the block 1 is made.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for protecting the bottom of a blast furnace, which can prevent local wear of carbon blocks at the bottom of a blast furnace and achieve a long life of the furnace body.

Conventionally, the bottom of a blast furnace has been mainly composed of carbonaceous refractories from the viewpoints of well-known hot metal resistance, slag resistance, old alkalinity, and cooling effect. However, due to long-term operation, the refractory block (hereinafter referred to as carbon block) will gradually wear out from the inside of the furnace, and a weak layer will form inside the carbon block due to thermal effects. The ability to protect the structure is weakened, the rate of wear increases rapidly, and this results in localized melting (i.e., Norakuro-type erosion). Because it becomes a problem,
If so, either spray water from the outside of the iron skin to completely cool the carbon block, or else! It is known that a method of installing a cooling structure in the bottom of the hearth in the construction mf in advance, as described in the '17-46353 publication, or of arranging all the staves for σ and Pζ, etc. . Even if such measures as Shito and Shiko are used on Fridays, the cooling effect will be
Since it does not reach the b-plane (bath contact surface), the wear rate does not reach K, which decreases the total width KN, and therefore it is difficult to achieve stable blast furnace operation for a long period of time.

This invention was made in order to determine the above-mentioned molten point kA'l, and its characteristics are as follows. A cooling medium (eg, gropan gas, etc.) is completely extracted through a communicating cooling medium flow path, and the cooling medium is completely extracted. The cooling effect caused by the decomposition heat of the blasting medium causes deposits of hot metal or slag to form on the molten metal contact surface (the working surface of the carbon block) of the furnace bottom and the lower peripheral wall of the Gb fm. An object of the present invention is to provide a method for protecting the bottom of a blast furnace, which can extend the life of the bottom of the furnace.

As a result of extensive research conducted prior to the completion of the present invention, the inventors of the present invention discovered that, in place of the conventional means for enhancing cooling capacity from the outside of the furnace to the bottom of the furnace, the molten metal contact surface of the refractory, the so-called working surface, The present invention was completed by focusing on the fact that the deposits formed by cooling the hot metal or slag are removed, and that the deposits completely protect the refractories at the bottom of the furnace.

As the above-mentioned deposit-forming substance or cooling medium, it is also possible, for example, to blow in hydrocarbons such as methane, ethane, glopane, butane, or light oil in vapor form.

Moreover, it is also blown into a gas having a high hydrocarbon content, such as natural gas or coke oven gas.

The passage of the cooling medium into the furnace as described above can be realized by forming a passage for the cooling medium in the bottom refractory of the furnace, and one embodiment of this will be described below based on the drawings.

The carbon block J at the hearth bottom is built step by step from the hearth bottom surface plate 2, and at the top of the number of lights, as shown in Figure 4, there is a hole through which the cooling spy 7°3 passes inside the carbon block. 4
Apply the one with the perforation.

The block 1 provided with the holes 4 is constructed from one shell side parallel to the radius of the blast furnace shell. In this case, after the blocks 1 are loaded, a pipe 3 through which a cooling gas passes is installed. 1 for cooling? If Eve 3 is made slightly longer than the length of the car block, the core will not shift and piping will be easier after the block is constructed.

When installing a vertical cooling gas outlet on the bottom of the furnace, attach the vertical outlet nozzle 5 to the pipe 3 of the carbon block 1 easily by fitting it into the hole 6 previously made in the block 1. Can be installed. These pipes (nozzles) are joined by welding, and conventional mortar is used for the joints between the carbine blocks 1.

In this way, a stack of carbon blocks is completed in which the cooling pipes 3 are sequentially incorporated into the carbon blocks 1.

The arrangement of the cooling nozzles is based on the normal Noracro erosion line 7, and they are placed mainly in the hearth bottom corner part 13 where wear and tear is extremely large. For example, every 1 m in the circumferential direction, and every 1.5 m in the radial direction.

The shape of the nozzle 3 is a double-tube type nozzle in which an inner via ``8'' and an outer pipe 9 are combined with a slight gap, and the nozzle is inserted into the hole 4 of the block 1 using mortar 10 or the like.Inner tube The diameter of 8 is 10~30111111
% The clearance with the outer pipe should be on the order of several yen, and the mortar should be 10
It can be easily attached by installing it on the carbon block 1 using. Further, the entire nozzle may be made of refractory material, motherboard, or porous plug.

In this way, the carbon block 1 containing the pipe 3 for flowing the cooling gas is constructed and then joined to the gas main pipe 12 outside the furnace. If the gas main pipe 12 is built into the car pin block 1 and divided into one for the number of lamps and one for the furnace bottom wall according to the number of fr-/el 3b, a stable cooling gas can flow. Furthermore, in order to prevent heat shock to the carbon block 1 at the initial stage of firing, clay bricks are usually constructed on the working surface side, but in this case, blow holes for cooling gas are provided and the construction is modified.

After ignition, the blowing of the cooling gas into the nozzles 3aJ:p of the carbon block 1 of the number of lamps is started from the time when the hot metal starts to be generated. Blast furnace operation is Ill [il F? When the amount of pig iron tapped starts to increase, the clay bricks on the working side will probably wear out and fall off. After that, the hot metal around the nozzle 3b is cooled by the action of the cooling gas, and the nozzle outer tube 9 and the mortar 1
A molten pig iron kimono, which uses the moving surface of the 0 as a foothold, begins to form. This is because wear and accumulation are balanced by the thickness of the culm depending on the temperature and movement of the hot metal, and a protective wall that eventually envelops the carpin block 1 can be created. In other words, wear and tear on the carn block 1 is prevented by the wall of the hot metal itself.

Although there is a view that it is dangerous to open a hole in the bottom of the blast furnace from the beginning, there is no problem because the flow of hot metal into the nozzle 3b can be prevented by blowing cooling gas at about the speed of sound. Further, when it is desired to close the nozzle 3b, it is possible to immediately block the nozzle 3b by pushing the filler in with an amorphous filler filling device such as a mud gun, which can also be used to prevent accidents.

The specific method for creating the hot metal protective wall is to maintain the cooling gas blowing speed at about 330 m/s.

This causes the base metal to adhere to the nozzle 3b.

Also, by changing the speed, it is possible to spread the base metal and make it flat.

The base metal adhesion created in this way creates a suitable protective wall on the surface of the force-zen block 1 and prevents the carbon block 1 from being eroded. Since the wear and tear of the blocks is suppressed in this way, the bottlenecks of conventional blast furnace linings are eliminated, a longer service life is achieved, and the blast furnace can be operated smoothly.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the carden block lining at the bottom of the blast furnace where cooling gas piping is installed, Figure 2 is the cooling gas injection nozzle, and Figures 3 and 4 are the cooling arrangement inside the carbon block. τ? A standing view showing the. 1: Force-pin block, 3: Cooling/Izo, 3b: Nozzle, 4 Hole in the nib block, 8: Inner tube, 9: Outer tube, 10
:mortar

Claims (1)

[Claims] A cooling body is passed through a cooling medium channel provided in the bottom of the blast furnace and a lower wall of the sump part that is continuous with the bottom of the furnace, and communicates with the inside of the furnace. A method for protecting the bottom of a blast furnace, characterized by completely forming a crack on the contact surface.