JPH10251718A - Bell-less type furnace top charging device in blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately charge coke into the center part of a furnace to secure the ventilation of raw material charged into the blast furnace. SOLUTION: An opening hole 8 is arranged on a chute surface 15 at the position in a swing chute 5 holding a fixed inclining angle corresponding to the center axis of the blast furnace body. Therein, the center charging chute 9 is vertically arranged downward and also, the opening hole 8 is freely opened/ closed with a switching damper 10. At the time of closing the opening hole 8 with the switching damper 10, the raw material is charged into the furnace from the tip part of the swing chute 5. Further, at the time of opening the opening hole 8 by shifting the switching damper 10, the raw material is accurately charged into the center part of the furnace from the opening hole 8 through the center charging chute 9 without spattering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for optimizing a distribution of raw materials in a furnace in a radial direction through a swirling chute disposed at a furnace top of a blast furnace. And a bellless type furnace top charging apparatus for a blast furnace capable of accurately performing the process.

[0002]

2. Description of the Related Art In blast furnace operation, raw materials such as iron ore such as sinter ore and coke are alternately charged into a furnace in layers. The raw materials charged into the furnace are first dried and preheated by the high-temperature gas rising in the furnace, and the ore is reduced. It becomes metallic iron and becomes pig iron by absorbing carbon and accumulates in the furnace bottom. The pig iron accumulated in the furnace bottom in this way is taken out of the tap hole at the furnace bottom as hot metal to produce pig iron. In order to improve the productivity of the blast furnace and the quality of pig iron, it is necessary to improve the gas permeability, smoothly lower the charged material, raise the gas with good gas permeability, and reduce the heat load on the furnace wall. It is required to reduce it.

[0003] Although the shape of the blast furnace is axially symmetric, its operation can be stabilized by appropriately controlling the distribution of the raw material charge in the furnace top radial direction, that is, the particle size distribution and the layer thickness distribution of coke and ore. It is necessary to optimize the gas flow distribution, the heat flow ratio distribution, and the resulting ore reduction and dissolution conditions in the circumferential direction. As a furnace top charging device that satisfies this condition, a bellless type furnace top charging device that has a greater degree of freedom in controlling the distribution of the raw material charge is adopted. Entrance control is being performed.

In the case of a bellless type furnace top charging apparatus, for example, as shown in FIG. 6, raw materials charged into a furnace are stored in, for example, two furnace top hoppers 1, 1. The raw material 6 stored in the furnace top hopper 1 is shut off from the outside air after the raw material reception is completed, and adjusted to the same pressure as in the high-pressure furnace. Furnace top hopper 1
After the internal pressure is adjusted, the gas is discharged by opening and closing the flow rate adjusting gate 2A provided at the outlet of the inclined chute 2 fixed to the lower part of the furnace top hopper 1. The raw material 6 discharged from the inclined chute 2 falls through the collecting chute 3 and the vertical chute 4 fixed below the collecting chute 3. The raw material that has fallen here is supplied to the outlet of the vertical chute 4 via a swivel chute support shaft 7 to a swivel chute 5 that is supported so that the inclination angle θ with respect to the vertical can be adjusted and swivel in the furnace circumferential direction. . The raw material 6 supplied to the revolving chute 5 slides down along the chute surface and is charged into the furnace by free fall from the tip of the chute.

In recent blast furnace operations, there is a need to use as much fine-grained ore as possible at the lowest possible cost in order to reduce the cost of raw materials. However, an increase in the amount of the fine-grained raw materials charged into the blast furnace causes an increase in gas flow resistance rising in the furnace. When the ventilation resistance in the furnace increases, the rising force is abnormally increased due to the rising gas, which causes a failure to lower the charge, and as a result, the amount of air supplied from the tuyere provided at the lower part of the blast furnace has to be suppressed. , And the output of the blast furnace must be reduced.

[0006] Inside the blast furnace, there is a so-called furnace core at the tip of the raceway formed by hot air blown from the tuyeres, where the movement of coke is small in a mountain shape. When the particle size of the coke constituting the mandrel is small, or when the porosity of the mandrel is reduced, the ventilation / liquid permeability of the mandrel deteriorates,
This causes an increase in the blowing pressure, frequent occurrence of slips, and deterioration of the waste property. To avoid this, preferentially insert coke with good air permeability into the blast furnace at the center of the furnace, secure a stable central flow of hot air in the furnace, and reduce the ventilation resistance in the furnace as a whole. It is a general method to stabilize the furnace condition of a blast furnace.

As a means for preferentially charging coke with good air permeability into the blast furnace at the center of the furnace as described above, a dedicated center charging device is installed separately from a normal blast furnace top charging device. (See Japanese Patent Application Laid-Open No. 60-56003).
In the case of a bellless type furnace top charging apparatus, as shown in FIG. 5, the raw material 6 is charged near the center of the blast furnace with the swiveling chute 5 being set in a substantially vertical posture with the swiveling chute support shaft 7 as a fulcrum. General. Since the revolving chute 5 performs revolving and tilting at the same time, it cannot be made completely vertical mechanically and is slightly tilted.
The part falls downward while colliding with the chute surface of the revolving chute 5. For this reason, the raw material 6 rebounded and scattered by the revolving chute 5 has a problem that the center of the coke cannot be accurately charged because the falling position on the raw material charging surface at the furnace top is widened.

[0008]

When a dedicated center charging device is installed separately from the existing ordinary blast furnace top charging device, the equipment cost is naturally extremely high and cannot be easily adopted. In addition, as described above, the method of charging the coke centrally with the swiveling chute as vertical as possible has a large variation due to the scattering of the raw material and the accuracy of the drop position is poor, so that the coke layer at the furnace center is stably formed. It could not be formed, making it difficult to ensure air permeability by the gas center flow.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bell-less furnace top charging apparatus for a blast furnace capable of solving the problems of the prior art and enabling high-precision central coke charging with low capital investment. As a result, it is possible to use a large amount of inexpensive fine ore.

[0010]

According to the present invention, there is provided a bellless type furnace top charging apparatus for a blast furnace provided with a swirling chute, wherein the swirling chute has a fixed inclination angle. An opening is provided at a position corresponding to the center axis of the blast furnace body on the chute surface of the chute, and a central charging chute having the same axis as the center axis of the blast furnace body is disposed downward in the opening. A bellless type furnace top charging device for a blast furnace, characterized in that a switching damper that opens and closes the opening by a rotation about a rotation axis provided at a downstream edge of the blast furnace is installed.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the present invention, the turning chute 5 is supported at the lower end of the vertical chute 4 via a turning chute support shaft 7 so as to be tiltable, as shown in FIGS. 1 and 2, and has a gutter-like shape having a flat bottom surface and side walls on both sides. The chute surface 15 is provided with an opening 8 at a position corresponding to the center axis A of the blast furnace body in a state of being inclined at a certain inclination angle. A central charging chute 9 connected to the opening 8 and having the same axis as the central axis A of the blast furnace body directed downward is provided in the vertical direction. A switching damper 10 is provided in an opening 8 provided in the turning chute 5 by a rotating shaft 11 provided in a downstream edge portion.
Are supported rotatably about the fulcrum.

A rotating shaft 11 penetrating the side wall of the turning chute 5
Has an arm 12 attached to one end thereof.
Is connected to a piston rod 14 of an air cylinder 13 disposed on the side surface of the revolving chute 5. When the piston rod 14 of the air cylinder 13 is expanded and contracted, the arm 12
Rotation is performed around the fulcrum 11, whereby the switching damper 10 moves between the open position and the closed position of the opening 8. In addition,
The arm 12 may be operated from a gear box via a link mechanism.

The tilt angle of the turning chute 5 when performing the center charging of coke can be set arbitrarily. However, since the load of the center charging chute 9 provided on the turning chute 5 needs to be received by the turning chute support shaft 7, Since it is advantageous to make the position of the center charging chute 9 as close to the support shaft 7 as possible, it is preferable to provide the opening 8 at a position corresponding to the central axis of the blast furnace furnace body with the inclination angle of the swirling chute 5 as large as possible. .

FIG. 3 shows a state in which a blast furnace is normally charged with raw materials by the bellless furnace top charging apparatus of the present invention.
In this case, the switching damper 10 provided on the turning chute 5
Is a state in which the opening 8 is closed, and the raw material 6 flows from the vertical chute 4 into the turning chute 5 which is turning at a predetermined inclination angle, and flows over the switching damper 10 in which the opening 8 provided in the turning chute 5 is closed. It is slid and distributed from the tip of the chute to a predetermined radial position on the furnace top charge in the blast furnace.

On the other hand, when charging the furnace center, the turning chute 5 is tilted to a predetermined angle at which the center charging chute 9 is vertically oriented as shown in FIG. 4 and the air cylinder 13 is operated. After the switching damper 10 is moved to the open position to open the opening 8, the raw material flows from the vertical chute 4 into the swivel chute 5. At this time, since the switching damper 10 is in the upright position with the rotating shaft 11 provided at the downstream edge of the opening 8 as a fulcrum, the raw material 6 is prevented from flowing from the switching damper 10 toward the tip of the turning chute 5 and 8 leads to the center charging chute 9. For this reason, all of the raw material 6 passes through the center charging chute 9, and coke can be reliably charged into the center of the furnace top in a state where scattering of the raw material is suppressed. As a result, the permeability of the raw material layer charged in the blast furnace at the center of the furnace is improved, and the central flow of hot air in the furnace is secured, enabling blast furnace operation using a large amount of inexpensive fine ore. Become.

The diameter of the opening 8 provided in the turning chute 5 and the diameter of the center charging chute 9 can be determined according to the amount of coke charged centrally according to the production scale of the blast furnace. Generally, the width of the turning chute 5 and the opening 8
Is advantageous because the deposition of the raw material 6 does not occur on the revolving chute 5. Although the shape of the opening 8 may be arbitrary, it is also preferable that the opening 8 be a quadrangle having one side in the chute width direction in order to prevent the deposition of the raw material 6 on the revolving chute 5.

[0017]

As described above, the bell-less type furnace top charging apparatus for a blast furnace according to the present invention has a position corresponding to the chute surface corresponding to the center axis of the blast furnace body while the rotating chute is maintained at a fixed inclination angle. A central charging chute is disposed vertically downward, and the opening can be opened and closed by a switching damper from above with a downstream edge as a fulcrum. When the opening provided in the turning chute is closed by the switching damper, normal raw material charging is performed from the tip of the turning chute, and when the switching damper is moved to open the opening, the raw material passes from the opening through the center charging chute. It is charged into the center of the furnace without scattering.

According to the present invention, since the same charging chute can be used for the normal charging and the central charging of the raw materials, the equipment cost is reduced. Since the central charging chute is mainly dedicated to the central charging of coke, it can be freely set in accordance with the characteristics of the equipment, and the target central charging of the coke is achieved with high accuracy. As a result, a sufficiently stable central flow of hot air in the furnace can be obtained, and the blast furnace can be operated by using a large amount of inexpensive fine-grained ore, and the obtained effect is enormous.

[Brief description of the drawings]

FIG. 1 is a side view showing a turning chute according to the present invention.

FIG. 2 is a front view showing a turning chute according to the present invention.

FIG. 3 is a side view showing a normal charging state of the raw material by the swirling chute according to the present invention.

FIG. 4 is a side view showing the state of charging the raw material into the center by the turning chute according to the present invention.

FIG. 5 is a side view showing a state in which raw materials are charged centrally by a conventional swiveling chute.

FIG. 6 is a longitudinal sectional view showing a conventional bellless type furnace top device for a blast furnace provided with a swirling chute.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace top hopper 2 Inclined chute 3 Collecting chute 4 Vertical chute 5 Revolving chute 6 Raw material 7 Revolving chute support shaft 8 Opening 9 Center charging chute 10 Switching damper 11 Rotary shaft 12 Arm 13 Air cylinder 14 Piston rod 15 Chute surface

Claims (1)

[Claims] 1. A bellless type furnace top charging apparatus for a blast furnace provided with a swirling chute, wherein the swiveling chute corresponds to the center axis of the blast furnace body when the swiveling chute holds a constant inclination angle. And a central charging chute having the same axis as the central axis of the blast furnace body is disposed downward in the opening, and the rotation axis provided at the downstream edge of the opening is used as a fulcrum. A bellless type furnace top charging device for a blast furnace, wherein a switching damper that opens and closes the opening by rotation is installed.