JP2779277B2 - Removal method of residual raw materials in the blast furnace after blowing off the empty furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing residual materials in a furnace after blowing off a blast furnace, and in particular, scraping out only residual materials in the furnace after blowing off the blast furnace, and then repairing the inside of the furnace. It is particularly suitable when applied in the case of so-called simple refurbishment in which reheating is performed afterwards.

[0002]

2. Description of the Related Art First, an outline of a normal blast furnace operation will be described with reference to FIG. Ore and coke, which are raw materials, are alternately carried by a charging conveyor 13 and supplied into the furnace body 1 via a bifurcated chute 12, a fixed hopper 11, a small bell 10, and a large bell 9. The supplied raw material 2 includes an annular pipe 7, a tuyere connecting pipe 8.
The molten metal is reduced and melted by the hot air blown through the furnace, accumulates at the furnace bottom, periodically opens the tap hole 4, and is taken out to the torpedo 6 via the tap trough 5.

[0003] When repairing the blast furnace and the like, it is necessary to temporarily stop the operation of the blast furnace. However, when the blast furnace is blown off, if the raw material in the furnace is filled in the entire furnace, a great deal of labor is required to scrape the material. For this reason, a method of burning the charged material to the tuyere level, which is referred to as empty furnace unloading as shown in FIG. 3, is employed, and after the empty furnace unloading remaining below the tuyere level. The main method is to remove the furnace raw material 14 and the furnace melt 3 accumulated at the furnace bottom. Prior to blowing off the air in the blast furnace, the cleaning operation with an increased coke ratio (5
~ 7 days). And the unloading starts 12 ~ 16
At least an hour before, the entire charge is replaced with coke to prepare for unloading.

[0004] As shown in FIG. 3, before scraping out the residual raw material 14 in the furnace, the melt 3 in the furnace is temporarily discharged from the taphole 4.
b and the torpedo 6 via the temporary tapping gutter 5b,
Thereafter, the steel shell in a region that does not interfere with the tap hole 4a and the temporary tap hole 4b is cut out and opened to a size (height H, width W) that can be carried by the earth-moving machine 16 such as a shovel or a bulldozer (FIG. 4). reference). After removing the refractory brick in the opening using dynamite or the like, the raw material remaining in the furnace was scraped out. In FIG. 3, reference numeral 15 denotes a scraping machine 16 for scraping.
Is a provisional ramp for introducing the gas into the furnace.

[0005]

As described above, conventionally, in order to remove the residual raw material in the furnace to the outside of the furnace, not only temporary tap holes and ramps, but also fire refractory bricks in the opening of the shell. There are drawbacks, such as the need for enormous costs and many days, such as the restoration of a building. The present invention advantageously solves the above-mentioned problem, and eliminates the need for temporary tapholes and ramps, as well as notching and opening holes in the steel shell, and allows the residual material in the furnace to be easily and simply removed from the furnace. An object of the present invention is to propose a method for removing residual raw materials in a furnace after blowing off an empty furnace of a blast furnace that can be removed.

[0006]

That is, according to the present invention, the supply of the charge into the furnace is stopped and the charge level is gradually lowered to the tuyere level while blowing air from the blast furnace tuyere is continued. At the time of blowing off the empty furnace of the blast furnace to be blown out, replace the entire furnace interior with coke with a size of 100 mmφ or less before starting the blowing off, and then blow off the steel.After the blowing off, open the steel shell. After that, the tip of the suction hose is inserted into the furnace from the tuyere opening, and the hose removes the residual raw material in the furnace above the taphole level by the hose to the outside of the furnace. This is a method of removing residual materials in the furnace.

[0007]

According to the present invention, when suctioning with a hose, if the coke size is large, the hose is clogged or caught at the inlet of the suction port and the efficiency is reduced, so the coke size to be charged before blowing is reduced. It is especially important to keep. The coke used during normal blast furnace operation is direct coke from a coke oven, which is sieved with a screen of a coke plant or blast furnace plant and has a grain size adjusted to about 35 to 150 mmφ. And the remaining raw material 14 in the furnace shown in FIG.
Since the above is occupied by coke having a size of 100 mmφ or more, the suction efficiency of the vacuum is reduced.

According to the inventors' research on this point,
The size of the residual raw material 14 in the furnace in the unloading state is 100 mmφ
It has been found that when the pressure is equal to or less than 80 mm, the residual coke can be efficiently removed by suction without causing clogging of the hose or catching at the inlet of the suction port. As such fine-grained coke, yard stock coke and the above-mentioned under-screen coke during normal operation are advantageously adapted. Because the yard stock coke,
This is because the powder is pulverized during handling and the maximum diameter is about 100 mm or less, and the total amount of coke under the sieve is 35 mmφ or less. Even if such fine-grained coke is used, the charging of the ore is cut before the unloading, and the charged material is entirely coke. Therefore, there is no possibility that the air permeability deteriorates. In addition, since it is not necessary to use expensive large lump coke, and small lump coke which is advantageous for scraping-out work is used, it is also advantageous in terms of cost reduction.

[0009]

EXAMPLE After a normal cleaning operation, a cleaning operation was performed for 6 days, and then an empty furnace blowing operation was performed. At the end of this cleaning operation, yard coke with a particle size of 100 mm or less was used as the furnace interior material. After blowing off, the inside temperature of the furnace is lowered to room temperature by spraying water, etc., and as shown in FIG. 1, the tuyere connecting pipe 8, the cooling box 20 and the blower tuyere 21 are removed. Then, the worker 22 carried the vacuum hose 23 into the furnace and started sucking the residual material in the furnace. FIG. 1
Reference numeral 17 is a blast furnace steel shell, 18 is a tuyere frame tube seat, 19 is a tuyere frame, and 24 is a vacuum car.

[0010] The vacuum car 1 in the above removal work
The processing capacity per unit was about 1 m ³ / h. In addition, since the vacuum work was performed, there was no dust generated, and the work could be performed smoothly without any dangerous work such as heavy equipment work. Since there is no need to insert heavy equipment into the furnace, the steel skin notch of the conventional method was unnecessary, and the workers could freely enter and exit the existing tuyere opening (900 mmφ).

[0011] Table 1 shows the construction period, cost, and cost for the case where the unloading was performed using fine coke as the final charge according to the present invention and the case where the unloading was performed simply according to the conventional method.
The safety and working environment are shown in comparison.

[0012]

[0013]

Thus, according to the present invention, after blowing off the blast furnace from the blast furnace, there is no need to temporarily set up a temporary tap hole or a ramp, or to cut out and open a hole in the steel shell as in the prior art. The residual material inside can be easily and simply removed from the furnace.

[Brief description of the drawings]

FIG. 1 is a diagram showing a procedure for removing residual materials in a furnace according to the present invention method.

FIG. 2 is a schematic view of a blast furnace.

FIG. 3 is a diagram showing a situation in a furnace after blowing off an empty furnace.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blast furnace body 2 Furnace raw material 3 Furnace melt 4a Tap hole 4b Temporary tap hole 5a Tap hole 5b Temporary tap hole 6 Topped car 7 Annular pipe 8 Tuyere connection pipe 9 Large bell 10 Small bell 11 Fixed hopper 12 Fork chute 13 Charge conveyor 14 Furnace residual material after blow-off of empty furnace 15 Temporary ramp for scraping out furnace 16 Civil engineering machine for scraping 17 Blast furnace steel 18 Tuyere frame pipe seat 19 Tuyere frame 20 Cooling box 21 Blow tuyere 22 Worker 23 Vacuum hose 24 Vacuum car

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C21B 7/00 304 C21B 5/00 315

Claims (1)

(57) [Claims] Claims: 1. While blowing air from a tuyere of a blast furnace, the charging of the charge into the furnace is stopped, and the level of the charge is gradually lowered to the tuyere level. Before the start of the blowing, the entire volume inside the furnace and the size of the coke having a size of 100 mmφ or less are replaced, and then the blowing is performed. After the discharging, the tuyere is opened without opening the steel skin. Inserting the tip of a suction hose from the opening into the furnace, and sucking and removing residual raw materials in the furnace above the taphole level to the outside of the furnace by using the hose. How to remove residual raw materials.