JPH1081910A - Tuyere ring for blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage of a refractory-made tuyere ring and to operate a blast furnace under stable condition to the blasting speed in the tuyere. SOLUTION: A metal-made tuyere ring 3 and a refractory-made tuyere ring 2 having the outer shape corresponding to the inner surface of the tuyere 1, are arranged in series in the inner surface of the tuyere so as to position the metal-made tuyere ring 3 at the center side of the blast furnace and the refractory-made tuyere ring 2 at the outer peripheral side of the blast furnace. The metal-made tuyere ring 3 has the length of >=20mm in the radial direction of the blast furnace to protect the refractory-made tuyere ring 2. The refractory- made tuyere ring 2 is protected from thermal and mechanical shocks in a raceway and the blasting speed in the tuyere is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tuyere ring for a blast furnace, which is mounted on the inner surface of a tuyere and can adjust the wind speed of the tuyere.

[0002]

2. Description of the Related Art Tuyere wind speed is an important factor for determining the amount of heat supplied to a stagnant region in the lower part of a blast furnace, that is, the furnace core. In order to increase the heat supply amount, it is preferable to increase the tuyere wind speed as much as possible. However, with the increase of the tuyere wind speed, powdering of coke due to mechanical impact at the tuyere tip becomes remarkable. If the amount of pulverization is too large, stable operation of the blast furnace will be hindered. Therefore, it is very important to appropriately adjust the wind speed at the tuyere tip according to the operation state in order to maintain stable operation. Therefore, in Japanese Utility Model Publication No. Sho 60-26117, a multiple tuyere ring in which a plurality of refractory tuyere rings whose diameters are sequentially reduced is fitted coaxially is mounted on the inner surface of the tuyere, and from the time of burning operation to the time of normal operation. The wind speed at the tuyere tip is controlled to be constant by removing the tuyere ring of small diameter stepwise according to the wind speed increase in the whole process.

[0003]

However, in such a multiple tuyere ring, there is a problem in durability of a portion which receives heat and mechanical shock. In other words, the raceway formed at the tuyere tip inside the blast furnace is the hottest space due to the combustion of the pulverized coal and coke injected. Further, the velocity of the hot air blown into the blast furnace is the highest, and is the area where the mechanical shock is the largest in the blast furnace.

On the other hand, the tuyere ring is made of a refractory which is easily damaged by impact. Therefore, the tip of the tuyere ring closest to the raceway is often damaged by mechanical impact. A tuyere ring with a broken tuyere ring cannot not only achieve the target tuyere wind speed, but also cause an imbalance in the amount of air blown in the circumferential direction of the blast furnace. The present invention has been devised to solve such a problem, and by arranging a refractory tuyere ring and a metal tuyere ring in series in the tuyere, the heat and mechanical properties of the raceway are improved. It is an object of the present invention to provide an inexpensive tuyere ring in which damage due to impact is suppressed and the tuyere wind speed is maintained at a target level even if the tuyere ring is broken.

[0005]

In order to achieve the object, a tuyere ring for a blast furnace according to the present invention comprises a metal tuyere ring and a refractory tuyere ring having an outer shape coinciding with the inner surface of the tuyere. The tuyere ring is arranged in series on the inner surface of the tuyere so that the metal tuyere ring is located on the center side of the blast furnace and the refractory tuyere ring is located on the outer peripheral side of the blast furnace. The metal tuyere ring is made of a metal having a high thermal conductivity, for example, copper in order to utilize the effect of tuyere cooling, and has a length of 20 mm or more in the radial direction of the blast furnace. The metal tuyere ring is arranged in the tuyere so that the tip thereof coincides with the tip of the tuyere on the blast furnace center side.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tuyere 1 according to the invention is constricted towards the inside of a blast furnace. The outer shapes of the refractory tuyere ring 2 and the metallic tuyere ring 3 are formed in accordance with the inner surface of the tuyere 1. The tuyere rings 2 and 3 are arranged in series on the inner surface of the tuyere 1 toward the center of the blast furnace 4 with the refractory tuyere ring 2 being on the outside of the blast furnace and the metal tuyere ring 3 being on the inside of the blast furnace. The tuyere rings 2 and 3 have the same thickness so that a step does not occur at the joint. Since the volume, pressure and temperature of the air fed into the blast furnace 4 are known in advance, the tuyere wind speed in the blast furnace 4 using the tuyere 1 narrowed toward the inside of the blast furnace is the most reduced in the tuyere 1. It is determined by the inner diameter at the tip 1b. Therefore, the tip of the metal tuyere ring 3 is aligned with the tip 1b excluding the tip curved portion 1a on the inner circumference of the tuyere,
The tuyere wind speed is changed by changing the thickness of the metal tuyere ring 3. The thickness of the metal tuyere ring 3 can be changed by replacing the tuyere ring when the blast furnace 4 is closed. The curved portion 1a at the tip of the tuyere has a curved shape in order to equalize the effect of the cooling water circulating in the tuyere 1 used in the present invention.

With this arrangement, the refractory tuyere ring 2
Are protected by the metal tuyere ring 3 from the heat and mechanical shock of the raceway 5. Further, even if the refractory tuyere ring 2 is damaged, the target tuyere wind speed is maintained by the metal tuyere ring 3 which is resistant to heat and mechanical shock. Moreover, the combination of the refractory tuyere ring 2 and the metallic tuyere ring 3 not only reduces the heat loss due to tuyere protection and tuyere cooling, but also allows the tuyere wind speed to be easily changed. The length of the metal tuyere ring 3 in the blast furnace center direction is the refractory tuyere ring 2.
It is preferably 20 mm or more from the viewpoint of preventing breakage of the film.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Inner surface of a tuyere 1 in which a metal tuyere ring 3 made of various metals having different thermal conductivities is provided in a blast furnace 4 having an inner volume of 2650 m ³ in series with a refractory tuyere ring 2. Was placed. After operating the blast furnace 4 for two months using the tuyere 1, the state of damage to the tuyere 1 was investigated. As can be seen from the survey results in Table 1, the higher the thermal conductivity of the metal material, the stronger the cooling effect and the more the metal material was suppressed from being damaged. In fact, in the case of a copper tuyere ring having high thermal conductivity, no breakage due to heat and mechanical shock of the raceway was detected.

[0009]

In addition, a copper tuyere ring 3 having a different length in the blast furnace center direction is arranged in series with the refractory tuyere ring 2 in the tuyere 1 of the same blast furnace 4, and the blast furnace operation is continued for two months. . Two months later, the tuyere 1 was removed from the blast furnace 4, and the state of damage to the refractory tuyere ring 2 was examined. As can be seen from the investigation results in Table 2, the tuyere ring 3 having a length of 20 mm or more in the center direction of the blast furnace had no damage to the refractory tuyere ring 2. This indicates that when the length of the copper tuyere ring 3 in the direction of the center of the blast furnace becomes 20 mm or more, the influence of heat and mechanical shock of the raceway no longer reaches the refractory tuyere ring 2.

[0011]

[0012]

As described above, in the tuyere ring of the present invention, the metal tuyere ring is arranged in series with the refractory tuyere ring at the center of the tuyere at the center of the blast furnace. This prevents damage to the refractory tuyere ring due to the heat and mechanical shock of the way. Also, even if the refractory tuyere ring is damaged, the metal tuyere ring remains in the tuyere without being damaged, so that the target tuyere wind speed is maintained and the blast furnace is operated under stable furnace conditions. You.

[Brief description of the drawings]

FIG. 1 is a sectional view of a blast furnace tuyere in which a refractory tuyere ring and a metal tuyere ring are arranged in series.

FIG. 2 is a schematic diagram showing the inside of a blast furnace around tuyere.

[Explanation of symbols]

1: Tuyere 1a: Curved tip of tuyere 1b: Tip of tuyere 2: Tuyere ring made of refractory 3: Metal tuyere ring
4: Blast furnace 5: Raceway

Claims (2)

[Claims] 1. A metal tuyere ring and a refractory tuyere ring having an outer shape corresponding to the inner surface of a tuyere, wherein the metal tuyere ring is on the center side of the blast furnace, and the refractory tuyere ring is on the outer peripheral side of the blast furnace. A tuyere ring for a blast furnace arranged in series on the inner surface of the tuyere so as to be located at 2. A tuyere ring for a blast furnace according to claim 1, wherein a metal tuyere ring having a length in the radial direction of the blast furnace of 20 mm or more is arranged in the tuyere with its tip coinciding with the tip of the tuyere on the center side of the blast furnace. ring.