JPH046761B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method of charging raw materials in a vertical furnace such as a blast furnace and an apparatus used in the method (Prior Art) For example, as a bellless furnace top charging device for charging raw materials,
Some are described in Publication No. 34082.

In this bellless furnace top charging device, as shown in FIG. With one of the upper seal valves 4-1 open, the materials are loaded into the fixed hopper 5-1 on one side of the two fixed hoppers.
When the raw material charging is completed, the upper seal valve 4-1 is closed, and the pressure inside the fixed hopper 5-1 is equalized with blast furnace gas or nitrogen gas to be equal to the furnace top pressure.

Next, the lower seal valve 7-1 is fully opened,
The raw material discharge amount is adjusted by the gate valve 6-1, and the in-furnace chute 11 is continuously tilted and rotated to guide the raw material into the furnace so as to obtain a desired distribution shape in the furnace. And fixed hopper 5-1
While the raw material is being charged into the furnace 10, the switching chute 3 is rotated to charge and store the raw material into the fixed hopper 5-2 on one side in the same manner as described above.

As described above, the two fixed hoppers 5-1 and 5-2 are arranged at 180 degrees from the core core, and raw materials are alternately delivered from each hopper in batches to the furnace 10 according to the charging schedule. It is designed to be charged inside.

However, in such a conventional bellless furnace top charging device, the raw material is charged into the furnace 10 by continuously rotating the furnace chute 11 while maintaining it at the same tilt angle, so that the raw material input into the furnace is The charging distribution will not be uniform. This has been confirmed in experiments regarding powder and granular material flow in actual operating conditions and scale models, and the charging distribution within the furnace 10 is not uniform in the circumferential direction, resulting in a phenomenon in which the circumferential balance is disturbed.

This non-uniformity in charging distribution is caused by the fixed hopper 5-
The raw materials from 1 and 5-2 pass through the inverted conical collecting chute 8 and the vertical chute 9, and are transferred to the in-furnace chute 11.
When the raw material falls, the locus of the main line of the raw material deviates from the axis of the vertical chute 9 and the fixed hopper 5-
This is facilitated by the relative relationship between the positions of 1 and 5-2 and the rotating direction of the in-furnace chute 11.

The distribution of the raw materials as described above will be qualitatively explained with reference to FIG.

In the figure, the raw material discharged from the fixed hopper 5-1 is accelerated as it falls down the collecting chute 8, and the main line of the falling raw material in the vertical chute 9 is directed towards the center of the furnace 10 due to the inertia of the powder flow. The flow is biased toward the fixed hopper side 5-2 on the other side of the axis y-y.

Now, when the in-furnace chute 11 is at the position shown by the solid line, the collision position of the raw material against the bottom of the in-furnace chute 11 is on the tip side of the in-furnace chute 11 with respect to the furnace center axis y-y. On the other hand, when the in-furnace chute 11 is at the position shown by the imaginary line, the collision position of the raw material is closer to the rear end of the in-furnace chute 11 than the furnace center axis y-y.

In this way, the run-up distance of the falling raw material differs depending on the rotational position of the in-furnace chute 11, and as a result, the raw material discharge rate at the tip of the in-furnace chute 11 and the trajectory of the raw material falling into the furnace 10 differ. .

Due to the above factors, the distribution of the charging material in the furnace 10 is unbalanced with respect to the furnace central axis y-y, that is, the distances x ₁ and x ₂ of the piles of charging material from the furnace central axis y-y are inconsistent. It will bring about.

As a charging device to solve the problems of such a top charging device without a bell, JP-A-58-
Some are described in Publication No. 58211.

As shown in FIG. 6, two fixed hoppers 14 and 15 are arranged vertically on the central axis of the furnace 10, and a flow rate regulating valve 13 is provided at the lower end of the lower fixed hopper 15, and a vertical chute 9 is installed below the vertical chute 9. The raw material is vertically dropped into the furnace rotating chute 11 located therein, and is configured to prevent disturbance of the circumferential balance.

(Problem to be Solved by the Invention) However, if the fixed hoppers 14 and 15 are arranged above and below, the height of the furnace will inevitably increase, and in order to reduce the height of the device to the same level as the conventional device, it is necessary to , it is necessary to increase the diameter of the upper and lower fixed hoppers 14 and 15 to ensure capacity.

However, when the diameters of the hoppers 14 and 15 become large, the deposited raw material 12-2 in the lower fixed hopper 15
The particle size distribution in is conical in shape, with fine particles at the center and coarser particles farther away from the center in the radial direction.

Therefore, the raw material 12- in the lower fixed hopper 15
2 is distributed into the furnace through the vertical chute 9 and the rotating chute 11 in the furnace, the raw material deposited in the furnace 10 becomes unevenly distributed over time, and due to uncontrolled particle size changes, as the discharge time progresses, The drift also changes in a complicated manner.

Furthermore, the degree of this drift change is due to coke, ore,
It also varies significantly depending on the type of raw material such as pellets.
Particle size segregation in the circumferential direction within the charged raw material causes non-uniformity in the rising gas flow, lowering the utilization rate of gas in the furnace for the reduction reaction, inhibiting fuel ratio reduction, and becoming a factor in unstable furnace conditions. Ta.

The present invention aims to eliminate the drawbacks of such a bellless charging device having two fixed hoppers arranged above and below, and eliminates the unbalance in the charging material distribution caused by the mutual positional relationship between the fixed hopper and the rotating chute in the furnace. The purpose is to control the particle size distribution of the raw material in the furnace by actively utilizing the particle size distribution of the charged raw material resulting from the shape of the raw material piled in the fixed hopper.

(Means and effects for solving the problems) The present invention provides a raw material charging device for a vertical furnace having two hoppers arranged above and below, in which the distribution of the raw material to be charged into the upper hopper is controlled within the hopper. The raw material 12-1 with a controlled amount and particle size distribution is stored at a predetermined position in the lower fixed hopper 15, and the funnel flow in the lower hopper is used to control the particle size of the raw material charged into the furnace. This makes it possible to control time-series emission characteristics. Here, the cone angle 17 of the lower fixed hopper 15 is approximately
If the angle is set to 60 degrees or less, the center of the raw material layer 12-2 will be discharged first, and the periphery in the hopper and the area near the container wall will be discharged later, resulting in a flow situation called funnel flow. The order will be used to control the time series characteristics of the raw material particle size. A conceptual diagram of this flow is shown in Figure 2.

(Example) The present invention will be described below based on the example shown in FIG.

In this figure, parts that are the same as those of the conventional apparatus shown in FIGS. 4 to 6 are indicated by the same symbols.

In FIG. 1, reference numeral 16 denotes the throat of the rotating chute, which can be tilted at any angle.The throat 16 has a diameter such that the material discharged from the switching chute 3 does not become clogged at any angle of inclination, and the throat inclination angle When is maximum with respect to the perpendicular line,
The falling position of the raw material streamline discharged from the switching chute 3 is at least 0.5R from the center of the upper fixed hopper 14.
It is necessary to set the throat length so that (R: radius of the upper fixed hopper).

The lower part of the upper fixed hopper 14 is usually 3 or 4
2 ports are arranged around the furnace axis, and the raw material discharged from the upper fixed hopper 14 is discharged to the periphery in the lower fixed hopper 15 through these ports.

The other structure is almost the same as that shown in FIG. 6, but the lower fixed hopper 15 has a cone with an angle of 1.
7 is less than 60°.

In the above structure, the raw material input from the head pulley 2 of the belt conveyor 1 to the switching chute 3 is charged into the upper fixed hopper 14 through the tiltable throat 16 provided at the tip of the switching chute.

At this time, the raw material passes through the throat 16 whose inclination angle is set by a control system (not shown), and the natural falling direction of the raw material, which has a horizontal velocity vector, is forcibly changed and the raw material falls and accumulates. Adjust the position.

Therefore, by adjusting the inclination angle of the throat 16, the two-dimensional cross section of the deposited raw material 12-1 stored in the upper fixed hopper 14 becomes M as shown in the figure.
shape, or any distribution shape such as ∨ shape or ∧ shape. Usually, the raw material for blast furnace has a certain particle size range, so the upper fixed hopper 1
Due to natural classification, raw materials with relatively large particle sizes come to gather in the valleys of the distribution of raw materials deposited within 4. It is a known fact that the degree of natural classification is greater as the slope distance increases, so in the case of a ∨ shape or ∧ shape, many coarse particles gather in the valley. In this way, by changing the shape of the raw material deposited within the upper fixed hopper 14, the raw material particle size distribution and quantitative distribution in the radial direction within the hopper can be controlled.

Further, the lower part of the upper fixed hopper 14 has a plurality of gate valves 6, and by opening and closing the gate valves 6 and the plurality of upper seal valves 4 provided at the upper part of the lower fixed hopper 15, the inside of the upper fixed hopper 14 is controlled. The raw material 12-1 is discharged to the periphery within the lower fixed hopper 15. Furthermore, referring to the raw material flow passing through the gate valve 6, the peripheral raw material in the upper fixed hopper 14 flows down the hopper wall side in the raw material flow, and the central raw material in the upper fixed hopper 14 flows down the hopper center side. and as a result,
The raw material particle size distribution in the lower fixed hopper 15 is similar to that in the upper fixed hopper 14.

The lower fixed hopper 15 has a cone angle 17 with a gentle slope of 60° or less in order to realize a funnel flow of the raw material discharge flow, so that the raw material in the periphery of the hopper and the vicinity of the cone wall is in the late stage. The time-series particle size of the raw material discharged into the furnace is controlled by the synergistic effect of the raw material particle size distribution control in the upper fixed hopper and the raw material discharge funnel flow in the lower fixed hopper. for example,
If the raw material accumulation shape in the upper fixed hopper 14 is ∧-shaped, as described above, coarse particles will be deposited in the periphery of the lower fixed hopper 15 and in the vicinity of the cone wall, and the time-series coarseness of the discharged raw material will increase. Granulation characteristics can be obtained.

Here, in order to obtain stronger time-series coarsening characteristics of the discharged raw material, it is necessary to deposit the coarse raw material in the upper fixed hopper 14 near the wall surface of the hopper cone, which is the slowest discharge part in the lower fixed hopper 15. be.

For this purpose, it is necessary to make the outer angle 19 of the upper fixed hopper port part 70° or more.
Confirmed by scale model test. It has also been confirmed that if it is desired to obtain a time-series flat characteristic of the particle size of the raw material discharged into the furnace, this can be achieved by setting the raw material accumulation shape in the upper fixed hopper 14 to an M shape and suppressing the classification of the raw material as much as possible.

To confirm the above, Figure 3 a and b show the 1/10 scale model test results. Here, Fig. 3a shows the relationship between the upper fixed hopper port angle and the time-series discharge characteristics of the raw material particle size. When the port outside angle 19 is set to 70°, the raw material discharged into the furnace is This results in granulation characteristics. Figure 3b shows that when the shape of the raw material pile in the upper fixed hopper is changed from ∧ → M ₁ → M ₂ → ∨ shape, the grain size of the raw material discharged into the furnace changes over time from coarse grain characteristics to fine grain characteristics. It shows test results that can be changed.

The upper and lower fixed hoppers 14 and 15 are each equipped with an upper seal valve 4 and a lower seal valve 7, which are operated to maintain the inside of the lower fixed hopper 15 at the furnace pressure and atmospheric pressure by respectively operating them when charging raw materials. be able to.

According to the present invention, when the raw material inputted from the belt conveyor 1 is supplied into the upper fixed hopper 14 by the rotation of the switching chute 3, the distribution in the circumferential direction is made uniform, and the raw material falls through the throat 16 at the tip of the switching chute 3. It is supplied to the upper fixed hopper 14 while being subjected to position adjustment and other actions.

The most preferable deposition distribution according to the characteristics of the raw material can be obtained by processing the flow of the raw material in each component, and the raw material 12-1 is further discharged to the lower fixed hopper 15. The raw material particle size distribution in the upper stationary hopper 14 can be brought into the lower stationary hopper 15 through, for example, three or four ports.

In the lower fixed hopper 15, the hopper cone angle 17 is gently inclined, so that the raw material in the periphery of the hopper and in the vicinity of the cone wall is discharged last. Normally, the time required to charge the raw material into the lower fixed hopper 15 is on the order of 1/10 shorter than the time required to charge the raw material into the upper fixed hopper 14, so the degree of classification of the raw material inside the lower fixed hopper 15 is extremely small. Because it is small, the upper fixed hopper 1
The raw material particle size distribution within 4 is maintained.

From the above switching chute 3 to the lower fixed hopper 1
In the raw material flow between 5 and 5, the upper fixed hopper 1
In addition to charging the controlled raw material in the most appropriate form with controlled distribution in the lower fixed hopper 15, the controlled raw material is fed into the furnace 10 in a time-series manner with particle size controlled by funnel flow in the lower fixed hopper 15. It can be vertically dropped into the in-furnace chute 11. and,
In the supply to the furnace 10 via the in-furnace chute 11, the flow control valve 13 at the lower end of the lower fixed hopper 15
With the opening of the lower seal valve 7, the discharge flow flows through the furnace 1 without causing a non-uniform particle size distribution in the circumferential direction.
0 vertical chute 9. Since the flow inside this vertical chute 9 does not cause drift, a lower fixed hopper 15 is installed in the in-furnace chute 11.
It is possible to supply controlled raw materials as they are.

Note that the number of gate valves 6 and upper seal valves 4 is determined by the amount of raw material charged into the furnace 10, the time schedule, and the allowable range of equipment height.

(Effects of the Invention) The present invention makes it possible to uniformize the distribution in the circumferential direction in the furnace with respect to variable factors such as the type and amount of charging raw material, and moreover, the operator can control the particle size of the raw material charged into the furnace. The effect is that the particle size distribution in the radial direction inside the furnace can be created as intended by freely controlling the time series.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view of the charging device of the present invention, Fig.
Figures a and b are schematic diagrams of funnel flow in a typical hopper, Figures 3 a and b are graphs showing 1/10 scale model test results of raw material particle size time series discharge characteristics in the lower fixed hopper, Figures 4 and 4 5 and 6 are schematic cross-sectional views of conventional examples. 1... Belt conveyor, 2... Head pulley, 3... Switching chute, 4... Upper seal valve,
5...Fixed hopper, 6...Gate valve, 7...Lower seal valve, 8...Collection chute, 9...Vertical chute, 10...Furnace, 11...Furnace chute, 1
2...Deposition raw material, 13...Flow rate control valve, 14...
Upper fixed hopper, 15...lower fixed hopper,
16...Turning shoot throat, 17...Cone angle, 19...Port outer angle.

Claims (1)

[Scope of Claims] 1. In a method for charging raw materials in a vertical furnace in which raw materials are charged to the top of a vertical furnace with two hoppers at the upper and lower parts, a first step of charging raw materials into the upper hopper In the second stage, the quantitative distribution and particle size distribution of the raw material in the hopper are controlled, and the controlled raw material is charged into the lower hopper and discharged into the vertical furnace. - A method for charging raw materials in a vertical furnace, which is characterized by converting the raw materials into a flow and supplying the raw materials to the top of the furnace while controlling the time-series discharge particle size of the raw materials. 2. A raw material charging device for a vertical furnace having an upper hopper having a rotating chute for charging the raw material from the conveying device, and a lower hopper arranged below the hopper and connected to the top of the furnace of the vertical furnace, In order to freely change the raw material flow line from the rotating chute, the tip of the rotating chute has a tiltable structure to control the raw material discharge flow line to the upper fixed hopper, and the inner surface of the lower hopper is connected to the raw material flow funnel.
A material charging device for a vertical furnace, characterized by having a gently sloped surface for flow.