JP2000328118A - Structure of blasting tube for blowing hot blast into blast furnace and method for changing blasting quantity from tuyere in blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change the blasting quantity from a tuyere without exchanging a tuyere itself, and also, without stopping the blasting for a long time, and to blow the hot blast into a blast furnace at a low cost without such fear as leakage of the blasting by arranging a difference in level not shorter than a specified length so as to form a larger diameter of the outside of the furnace than that of the inside of the furnace, in a blasting tube from the horizontal portion in a tuyere stock to the tuyere. SOLUTION: Hot blast is blown into the blast furnace 1 from the tuyere 2 through the blasting branch tube 5 branched from a blasting circulating tube, tuyere stock 6 and blow pipe 3. Further, since the difference part 8 in level is provided in the horizontal tube part 7 of the tuyere stock 6, an orifice for controlling the blasting quantity is inserted from an opening hole at the rear end part by removing a tuyere peeping glasses 9 and a cover 10 for the opening hole at the rear end part and can be fitted by staying to the difference part 8 in level. Time needed to execute this fitting is few min to ten and few min. The orifice for controlling the blasting quantity is made of a material capable of resisting to a high temp. such as >=1300 deg.C, concretely, a high alumina refractory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower tube structure for sending hot air to a tuyere attached to a blast furnace, and a method of changing the amount of blown air from the tuyere. More specifically, the present invention relates to a structure of a blower tube from a ring-shaped blower tube to a tuyere after branching, and a method of changing the amount of blown air.

[0002]

2. Description of the Related Art In a blast furnace, a plurality of tuyeres are attached to the lower part of the furnace at uniform intervals in a circumferential direction, and hot air is blown into the furnace from the tuyeres. Mounting the number of tuyeres is approximately forty degree in blast furnace having an inner volume of 4500 m ^3. The inner diameter of each tuyere is, in principle, the same in order to make each air volume of each tuyere uniform in principle.

FIG. 5 is a sectional explanatory view showing an example of a basic structure of a tuyere and a blower tube behind the tuyere. As shown in FIG. Behind the mouth 2, there is a blow pipe 3 and a tuyere stock 4.
Are attached in this order, and further attached to the tuyere stock 4 via a ventilation branch pipe 5 to a ventilation annular pipe (not shown). Therefore, the hot air blown into the blast furnace 1 is blown into the blast furnace 1 from the tuyere 2 through the blower branch 5, the tuyere stock 4, and the blow pipe 3 branched from the blower annular pipe.

In the operation of a blast furnace, there is a case where it is necessary to change or reduce the amount of air blown to a specific tuyere among a plurality of tuyeres attached in a circumferential direction of the blast furnace. For example, when changing the taphole depth, when local erosion of the bottom wall brick occurs, or when abnormal erosion of the shaft brick occurs, the tuyere immediately above the taphole is used. Change the air flow of In the case of, the amount of air blown from the tuyere immediately above where the local erosion has occurred is reduced. In the case of, the amount of air blown from the tuyere immediately below where abnormal erosion has occurred is reduced. In extreme cases such as severe erosion, the tuyere may be closed.

[0005] Specific techniques for changing or reducing the amount of air blown from the above specific tuyere include changing the amount of air blown by replacing the tuyere with a caliber equivalent to the required amount of air, or by using a special tuyere sho 63-65730. As described in Japanese Unexamined Patent Publication No. Hei 5-63522, a hot air control valve is provided in the air blow branch pipe behind the tuyere, and the amount of air blown to a specific tuyere is changed by controlling the hot air control valve. There is technology.

[0006]

However, when replacing the tuyere, the blast furnace is shut down and a replacement time of about one hour is required. In addition, when using a hot air control valve as described in the above publication, the hot air control valve is provided in advance in the blower branch pipe, so once installed, there is an advantage that control can be performed without shutting down the blast furnace. However, it is necessary to provide hot air control valves on all of the multiple air tuyeres provided in the circumferential direction of the blast furnace, which requires a large amount of cost for installation and a length of more than 20 hours. In addition to the need for timely wind-off, there is a concern about leakage from the hot air control valve mounting part.

Therefore, the present invention has been made based on the above-described circumstances, and changes the amount of air blown from the tuyere without replacing the tuyere itself and without taking a long time to shut off the wind. It is inexpensive and has no fear of leakage,
It is an object of the present invention to provide a blower tube structure for blowing hot air into a blast furnace and a method of changing the amount of blown air from a tuyere of the blast furnace.

[0008]

In order to achieve the above object, a blower tube structure for blowing hot air into a blast furnace according to claim 1 of the present invention has a structure in which a blower tube from a horizontal portion of tuyere stock to a tuyere is provided. And a step of 5 mm or more where the outside diameter of the furnace is larger than the inside of the furnace.

In the above configuration, a step is provided in the air duct extending from the horizontal portion of the tuyere stock to the tuyere so that the furnace outside has a large diameter with respect to the furnace inside. You can open and close the peephole (window etc. to look inside the tuyere) and fasten the orifice etc. for air volume control,
Thus, the amount of air blown from the tuyere can be changed without exchanging the tuyere itself and without stopping the air for a long time. The reason for setting the step to 5 mm or more is to surely keep an orifice or the like for controlling the air volume. In addition, in order to easily install an orifice or the like for controlling the air volume in the pipe of the stepped portion, it is necessary to make the cross-sectional shape in the pipe axis direction of the stepped portion more inclined than a vertical stepped shape. Preferably, it is formed in a convex shape having a curvature twice or more as large as (claim 2).

According to a third aspect of the present invention, there is provided a method for changing the amount of air blown from a tuyere of a blast furnace, wherein the outside diameter of the furnace with respect to the inside of the furnace is larger than that of the inside of the furnace. A step of 5 mm or more is provided, and an orifice made of a heat-resistant material having a diameter smaller than the inside diameter of the furnace is inserted into the step to control the amount of hot air into the furnace.

In the above-mentioned method of changing the air flow, the orifice made of a heat-resistant material attached to the stepped portion is attached or detached, or is replaced with a different-diameter one, or a small-diameter heat-resistant orifice is installed in the previously mounted orifice. By attaching or detaching the orifice made of a heat resistant material, a desired amount of hot air can be blown into the blast furnace from the tuyere of the blast furnace. In addition, the air volume can be changed by opening / closing the heat-resistant orifice, opening / closing the rear port of the tuyere stock at the rear end (the window for looking inside the tuyere, etc.). The amount of air blown from the tuyere can be changed without blowing.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional explanatory view showing a blower tube structure for blowing hot air into a blast furnace according to the present invention. The components constituting the blower tube structure are basically the same except for the structure inside the tube at the horizontal part of the tuyere stock. It has the same configuration as that shown in FIG.

That is, in FIG. 1, reference numeral 2 denotes a tuyere. The tuyere 2 is mounted in the blast furnace 1 with its tip facing, and a blower pipe (blow pipe) 3 and a tuyere stock 6 are provided behind the tuyere. Are attached in this order, and further attached to the tuyere stock 6 via a ventilation branch pipe 5 to a ventilation annular pipe (not shown).

The tuyere stock 6 is an elbow-shaped curved tube having a horizontal tube portion 7, and a step having a diameter of 5 mm or more in which the outside of the furnace has a large diameter with respect to the inside of the furnace is provided in the distal end tube of the horizontal tube portion 7. A portion 8 is formed, and tuyere viewing glasses 9 are attached to the rear end opening. In this example, the step portion 8 is a step h (= 10 mm),
It is formed on a convex curved surface having a curvature r (= 25 mm). Reference numeral 10 denotes a cover for the rear end opening.

In the above-mentioned blower tube structure, the hot air is blown by the blower branch pipe 5, the tuyere stock 6, which is branched from the blower annular pipe.
Since the tuyere stock 6 is blown into the blast furnace 1 through the blowpipe 3 and has a step 8 in the horizontal tube 7 of the tuyere stock 6, the orifice 11 for controlling the air volume is provided as shown in FIG. Tuyere viewing glasses 9 and rear end opening cover 10
Can be removed and inserted through the rear end opening, and can be fixed to the stepped portion 8 and attached. It takes several minutes to install
It can be done in ten minutes. The orifice 11 for controlling the air volume is 13
It is made of a material that can withstand a high temperature of 00 ° C or higher. A typical material is a high alumina (Al ₂ O ₃ )
₂ O ₃ 90% or more) is desirable.

Further, since the orifice 11 for controlling the air flow can be fixed to the stepped portion 8 as described above, when the taphole depth is changed during the operation of the blast furnace as described above, the furnace bottom side wall is required. When the local erosion of the brick occurs or the abnormal erosion of the brick of the shaft part occurs, the air flow rate is changed for a specific tuyere 2 of a plurality of tuyeres 2 installed in the circumferential direction of the blast furnace. When it is necessary to reduce or reduce the size of the tuyere 2, the orifice 10 for controlling the air flow is attached to the step 8 of the tuyere stock 6 of the specific tuyere 2 without replacing the tuyere 2 as in the prior art. In addition, it is possible to change the amount of air blown from the specific tuyere 2 to a desired amount and blow it into the blast furnace 1 without taking a long time to stop the wind.

FIG. 3 shows an example of the shape of the orifice 11 for controlling the air volume according to the present invention.
b is a case of a tapered orifice, c is a case of a right-angled orifice, and d is a case of a shape of an orifice with a projection. In this case, the inner diameter of the tuyere 2 is 130 mm, and the inner diameter of the horizontal tube 7 of the tuyere
The diameter of the orifice 11 was set to 100 mm. The result of measuring the air flow per tuyere 2 in this case is as shown in Table 1.

[0018]

[Table 1]

In the above example, the case where the step 8 is provided in the horizontal tube 7 of the tuyere stock 6 has been described as an example, but the present invention is not limited to this, and the tuyere 2 It may be provided in the ventilation branch pipe 3 between the tuyere stocks 6. Further, the shape of the step portion 8 is a convex curved surface, but may be a tapered shape. In addition, the example in which one air flow control orifice 11 is provided is shown in FIG. 4. As shown in FIG. Further control is also possible. By using an orifice without a hole, the ventilation can be closed. Furthermore, blast furnaces are usually pulverized coal,
Auxiliary fuel such as heavy oil, plastic, gas or the like is blown through the auxiliary fuel injection lance, and the orifice according to the present invention is mounted on the upstream side of the blower tube (the tuyere Side), there is no hindrance to these auxiliary fuel injections.

[0020]

As described above, according to the blower tube structure for blowing hot air into the blast furnace according to the present invention (claim 1), the inside of the blower tube from the horizontal portion of the tuyere stock to the tuyere is located inside the furnace. On the other hand, there is a step with a large diameter on the outside of the furnace,
An orifice or the like for controlling the air volume can be attached to the step and attached, so that the air volume from the tuyere can be changed without replacing the tuyere itself and without having to shut down for a long time. Can be.

According to the method for changing the amount of air blown from the tuyere of the blast furnace according to the present invention, the orifice made of a heat-resistant material attached to the stepped portion is attached or detached, or is replaced with one having a different diameter. By attaching or detaching the small-diameter heat-resistant material orifice to or from the previously mounted heat-resistant material orifice, a desired amount of hot air can be blown into the blast furnace from the tuyere of the blast furnace. In addition, the change of the air volume changes the heat resistant material orifice,
The opening / closing / replacement of the peephole at the rear end of the horizontal part of the tuyere stock (a window for peeking into the tuyere) can be performed, so that the amount of air blown from the tuyere can be changed without having to shut down for a long time. can do.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing a blower tube structure for blowing hot air into a blast furnace according to the present invention.

FIG. 2 is an explanatory sectional view showing an embodiment of a blower tube structure for blowing hot air into a blast furnace according to the present invention.

FIG. 3 is an example of the shape of an orifice for controlling air flow according to the present invention, wherein a is a case without an orifice, b is a case with a tapered orifice, c is a case with a right-angled orifice, and d is a case with an orifice with a protrusion. This is a shape example.

FIG. 4 is a mounting example of an air flow control orifice according to the present invention, in which a is a mounting case in which the orifice is double-mounted, and b is a mounting case in which the orifices are butted.

FIG. 5 is an explanatory sectional view showing a conventional blower tube structure for blowing hot air into a blast furnace.

[Explanation of symbols]

1: Blast furnace 2: Tuyere
3, 5: Ventilation branch pipe 6: Tuyere stock 7: Horizontal pipe section
8: Step 9: Tuyere viewing glasses 10: Cover at the rear end opening 11: Orifice for air volume control

Claims (3)

[Claims] 1. A hot blast is blown into a blast furnace characterized in that a step of 5 mm or more is provided in a blower pipe extending from a horizontal portion of the tuyere stock to the tuyere so that the furnace outside has a large diameter with respect to the furnace inside. Blow tube structure. 2. The blower tube structure for blowing hot air into a blast furnace according to claim 1, wherein the blower tube structure blows hot air into a blast furnace having a step formed on a convex curved surface having a curvature of twice or more the height of the step. 3. A step of 5 mm or more in which the outside of the furnace has a larger diameter with respect to the inside of the furnace, and a step having a diameter smaller than the inner diameter of the inside of the furnace is provided in the blower tube from the horizontal portion of the tuyere stock to the tuyere. A method for changing the amount of air blown from a tuyere of a blast furnace, characterized in that a heat-resistant orifice is inserted to control the amount of hot air into the furnace.