JPH08246011A - Method for charging raw material of blast furnace and device therefor - Google Patents

Abstract

PURPOSE: To reduce molten iron cost by eccentrically forming the supplying position of a raw material stored correspondingly to falling of the contents into a swing chute in regard to the center of a blast furnace. CONSTITUTION: The raw material is discharged from a furnace top hopper 1 and temporarily stored in a raw material storing chamber 2. A discharging gate 3 adjustable in the opening position and the opening degree is arranged at the lower part of the raw material storing chamber 2 and the falling of the contents in the blast furnace is observed, and the opening position and the opening area of the discharging gate are adjusted so that the falling in the furnace uniformizes. Then, the raw material is stored just above the swing chute 4 and the supplying position of the stored raw material stored correspondingly to the falling of the contents into the swing chute 4 is formed eccentrically in regard to the center of the blast furnace. The supplying position onto the swing chute 4 is determined based on the data obtained by pursuing a position, where the falling of the contents in the furnace uniformizes, and by storing the pursued data. The pursued data are also corrected by learning. By this method, furnace condition is stabilized and the frequency to reduce blast can also be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raw material charging method in a blast furnace.

[0002]

2. Description of the Related Art A blast furnace has an axially symmetrical shape, and it is necessary to make the reduction / melting reaction in the furnace axially symmetrical in order to stabilize the operation. In a blast furnace made in recent years, a bell-less type charging device is adopted as a charging device satisfying the above conditions. For example, in Japanese Utility Model Publication No. 59-5725, two hoppers having a discharge port on the central axis of the furnace are arranged vertically. The charging device is disclosed. In Japanese Patent Publication No. 61-30993, a cut gate is provided to throttle the flow in the vertical chute so that the raw material falls on the central axis of the furnace. Also, Japanese Patent Laid-Open No. 2-16
There is also known a charging device in which an auxiliary chute is attached in the turning chute to keep the material dropping position on the turning chute constant as in Japanese Patent No. 6209.

In any of these techniques, as shown in FIGS. 4 (a) and 4 (b), the flow rate adjusting gate is such that the center of the opening 53 formed by the slide gates 51 and 52 is at the blast furnace central axis (X, Y). It coincides with the Z direction axis of the intersection of the axes 54 and 55.

[0004]

It is desirable that the consumption of raw materials in the furnace of the blast furnace should not have a circumferential deviation, that is, it should be perfectly axisymmetric, so that it is necessary to eliminate the circumferential deviation in the charging of raw materials. Therefore, the bellless charging device as shown above was developed. However, in the actual blast furnace, it is rare that the raw materials are consumed uniformly in the circumferential direction,
There is a deviation in the circumferential direction of the descending speed of the raw material. There are several factors that cause the deviation of the falling velocity in the circumferential direction. Deposits generated on the furnace wall b. Furnace wall wear c. It is thought that the main cause is uneven air flow.

The charging of the raw material of the blast furnace is carried out when the height of the raw material surface at a certain position in the circumferential direction drops to a certain value. At this time, if the descent of the furnace contents 9 in the furnace is uneven as shown in FIG. 5, the radial distances 101 and 102 of the dropping positions of the raw materials 7 and 8 falling from the swirling chute are the contents of the furnace contents 9. It is on the furnace wall side in the fast descending direction, and on the furnace center side in the slow descending direction.

For this reason, the axial symmetry of the charged raw materials is further deteriorated, the circumferential deviation of the reduction / melting reaction in the furnace is further promoted, and finally a serious problem occurs that the stable operation of the blast furnace is impaired. To do.

[0007]

According to the technical means of the present invention, in a raw material charging method for a bellless blast furnace having a swirling chute, the raw material is stored immediately above the swirling chute and the contents of the blast furnace are lowered into the furnace. The raw material charging method of the blast furnace is characterized in that the feed position of the stored raw material to the swirling chute is eccentric with respect to the center of the blast furnace. In this case, the supply position to the swirling chute is tracked at a position where the furnace contents are evenly lowered in the furnace, the traced data is stored, the tracking data is positioned, and the stored data is corrected by learning. This is preferable.

A raw material charging apparatus for a blast furnace according to the present invention for carrying out the method of the present invention is a bell-less blast furnace top charging apparatus equipped with a swirling chute, and a raw material temporary storage chamber is provided above the swirling chute. The blast furnace raw material charging is characterized in that the bottom of the storage chamber is provided with an eccentric outlet in an arbitrary direction and at an arbitrary position, and a control device is provided for changing and controlling the position of the outlet based on observation in the furnace. It is a device. The discharge port may be an opening whose periphery is formed by four cut gates that are independently movable in the X and Y directions, and one pair of the cut gates in either the X direction or the Y direction is along an arc. It is preferable to use an arc-shaped plate cut gate that slides along the arc-shaped plate cut gate so that the other pair of cut gates are inscribed in the arc-shaped plate cut gate and slide in the arc axis direction.

[0009]

FIG. 3 shows an example of a mechanism for eccentricly dropping the raw material from the center of the furnace. A pair of arc-shaped plate-shaped cut gates 31 and 32 are provided at the lower end of the raw material storage chamber 2, and the sliding direction 3 is formed in an arc shape.
It is movable in 5, 36 directions. A pair of flat plate-shaped cut gates 33 and 34 are provided so as to form chutes along the arcs inside the pair of cut gates 31 and 32, respectively.
It can slide in 8 directions. These cut gates 31,
By independently moving 32, 33, and 34, the opening 39 formed at the center of these cut gates 31, 32, 33, and 34 moves its center in an arbitrary direction and by an arbitrary amount, and The size and shape can be changed freely. That is, the flow rate control gate of the present invention independently controls the north, south, east, and west gates as shown in FIG.
Eccentricity of raw material flow from the furnace center and flow rate (opening area)
Can be adjusted at the same time. Using this gate, the raw material dropping position is made to coincide with or eccentric to the furnace central axis as shown in FIGS. 1 (a) and 1 (b). That is,
When the swivel chute points to the right, the raw material falls to the tip side of the swivel chute, and when the swivel chute points to the left, it falls to the root side. As a result, the distance to slide the shoot 5,
When 6 is longer in the left direction, the speed at the tip of the raw material chute is higher.

FIG. 2 is a flow chart showing an embodiment of the method of the present invention. Observe the contents of the blast furnace before charging the raw materials and determine the next raw material supply position. At this time,
It is determined from the storage of simulation data and past performance data, and the gate position is changed according to this determination. Then, the raw materials are charged, the deposits in the furnace after the charging are observed, and it is observed whether or not a uniform descent is obtained. If they are not equal, a data correction signal is issued to correct the stored data. Since the blast furnace is not always in the same state, in the present invention, by performing trial-and-error learning control by learning by the above-described data correction, it is possible to always perform control that matches actual conditions.

A charging experiment was carried out using a cold model of 1/10 of the blast furnace. FIG. 6 is an explanatory view thereof, in which the raw material 8 is made to flow down from the hopper 1 through the raw material storage chamber 2 and the swirling chute 4 and deposited in the sampling box 91 arranged below the raw material 8. The flow rate control gate in the center of the furnace used in the model has two sets of two layers in the X and Y directions, and the raw material drop position can be freely moved within the range of the vertical chute opening. It is designed so that it can be eccentric from the center. The lower opening of the vertical chute of this experimental device has a diameter of 120 mm.

As shown in FIG. 7, raw material drop positions 93, 9
4 Center of vertical chute 2 and 50mm from the center
The position was changed to a biased position, and the drop position was measured by the sampling box 91. 50m from the center of the vertical chute when fed to the turning chute from the center of the vertical chute
FIGS. 8 and 9 show the falling positions in each azimuth when the tilt angles of the turning chute are 39 °, 43 °, and 52 °, respectively, when they are offset by m and supplied to the turning chute. It can be seen that changing the feed position from the vertical chute to the swirling chute has a strong effect on the drop position in the furnace.

In the experiment, after the coke was uniformly filled, the raw material was nonuniformly extracted and lowered, and then the ore was dropped into various positions in the vertical chute and charged into the furnace. FIGS. 10 and 11 show the situation. The difference between the left and right heights of the melt 9 in the blast furnace is 100 mm, the tilt angle θ (see FIG. 7) of the turning chute is 40 °, and the turning speed is 32 rpm (8 rpm in the actual machine). Equivalent to). The deposit shape before and after the ore charging was measured, and the difference between the measured values was the ore layer thickness.

When the raw material is dropped to the central axis position of the blast furnace in the vertical chute, the charge surface position is low on the side where the descending speed of the blast furnace contents is high, and the raw material falls to the furnace wall side. As shown in Fig. 10 (a), the ore layer thickness distribution showed a large difference between the left and right sides of the furnace cross section. FIG. 10 (b) shows this, and when the difference between the left and right heights of the blast furnace contents is 100 mm,
Profile 103 on the top surface of the charge is 1
04 was 40 mm. On the other hand, as shown in FIG.
When the raw material drop position from the vertical chute to the swirling chute is adjusted so that the right-hand drop position where the descent rate of the blast furnace contents is high is the furnace center side, the ore layer thickness deposition profile 1
03, the difference 104 on the left and right is 1 as shown in FIG.
It was observed that it was significantly improved to 7 mm. The optimum falling position in the vertical chute changes depending on the tilt angle and turning speed. It was optimal when the opening was positioned. In this case, the deviation of the ore layer thickness was reduced to less than half as described above.

[0015]

FIG. 1 shows an explanatory view of an embodiment of the present invention. The raw material is discharged from the furnace top hopper 1 and temporarily retained in the raw material storage chamber 2. An opening position and a size-adjustable discharge gate 3 are provided in the lower part of the raw material storage chamber 2 to observe the descent of the contents in the blast furnace into the furnace, and the opening position and the opening area of the discharge gate so that the descent into the furnace is uniform. Adjust. This adjustment simulation and past performance data are accumulated and learning control is performed. FIG. 2 shows the flowchart.

As an example, an improvement effect in a blast furnace having a bellless type furnace top charging device with a content responsibility of 4500 Nm ³ will be shown. By controlling the center position of the opening of the cut gate installed at the lower end of the vertical chute, the raw material is diverted from the vertical chute so that the raw material dropping position in the direction in which the descending speed of the blast furnace contents is fast is the central side of the furnace, as in the model experiment. Supplied to the turning chute.

FIG. 8 shows the deviation of the hot metal Si concentration, the deviation of eight skin flow thermometers indicating the uniformity in the circumferential direction of the upper part of the blast furnace, the hot metal temperature deviation, the hot metal temperature, the Si concentration in the hot metal, and ΔP /
Changes in V (pressure loss per air volume) and frequency of wind reduction are shown.
Due to the uniform balance in the circumferential direction of the charge,
The deviation of the Si concentration in the hot metal, the deviation of the skin flow thermometer, and the deviation of the hot metal temperature were all small, the hot metal temperature could be lowered, and the Si concentration in the hot metal could be made small. As a result, the refining cost in the downstream process can be significantly reduced, and a great advantage is obtained. In addition, the furnace conditions became stable and the frequency of wind reduction decreased, leading to a reduction in hot metal cost.

[0018]

According to the present invention, the hot metal temperature can be lowered, the Si concentration in the hot metal can be reduced, the furnace conditions can be stabilized, the frequency of wind reduction can be reduced, and the hot metal cost can be reduced. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the device of the present invention.

FIG. 2 is a flowchart of an example.

FIG. 3 is an explanatory diagram of a raw material flow rate adjusting gate according to the embodiment.

FIG. 4 is a plan view showing an example of a conventional raw material flow rate adjusting gate.

FIG. 5 is an explanatory diagram showing the relationship between the in-furnace descent rate deviation and the raw material dropping position.

FIG. 6 is a perspective view of a cold model experiment.

7 (a) is a side view and FIG. 7 (b) is a plan view of the turning chute.

FIG. 8 is a graph showing a drop position.

FIG. 9 is a graph showing a drop position.

FIG. 10 is an explanatory diagram showing a relationship between a descent rate deviation in a furnace and a raw material dropping position.

FIG. 11 is an explanatory diagram of an example.

FIG. 12 is a chart showing the effect of the example.

[Explanation of symbols]

1 Hopper 2 Raw material storage chamber 3 Discharge gate 4 Swirling chute 5,6 Distance 7,8 Raw material flow 9 Furnace contents 10 Furnace wall 31, 32, 33, 34 Cut gate 35, 36 Sliding direction 39 Opening 51, 52 Gate 53 Opening 54,55 Axis 91 Sampling box 93 Falling position 94 Falling position 10,102 Radial distance 103 Deposition profile 104 Deposition height

Claims (5)

[Claims] 1. A method for charging a raw material for a bellless blast furnace equipped with a swirling chute, wherein the raw material is stored directly above the swirling chute, and the stored raw material is fed to the swirling chute in response to the descent of the contents in the blast furnace into the furnace. A method for charging a raw material of a blast furnace, characterized in that the supply position is eccentric with respect to the center of the blast furnace. 2. The supply position to the swirling chute is such that the position where the contents of the furnace are uniformly lowered in the furnace is tracked, the tracked data is stored, the position is determined by the data, and the stored data is learned. The raw material charging method for a blast furnace according to claim 1, wherein the raw material charging method is modified. 3. A bell-top charging apparatus for a bellless blast furnace having a swirling chute, wherein a raw material temporary storage chamber is provided above the swiveling chute, and an eccentric discharge port is provided in the storage chamber bottom in an arbitrary direction and at an arbitrary position. A raw material charging device for a blast furnace, which is provided with a control device for changing and controlling the position of the discharge port based on observation in the furnace. 4. The discharge port is an opening whose periphery is formed by four cut gates, a pair of cut gates independently movable in the X direction and a pair of cut gates independently movable in the Y direction. The raw material charging device for a blast furnace according to claim 3, wherein 5. An arc-shaped plate cut gate in which a pair of cut gates in either the X direction or the Y direction slide along an arc, and the other pair of cut gates are inside the arc plate cut gates. The raw material charging apparatus for a blast furnace according to claim 4, wherein the cut gate is in contact with and slides in the direction of the arc axis.