JPH0333762B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for charging raw materials in blast furnace operation.

When charging ironmaking raw materials into a furnace during blast furnace operation, it is considered desirable that the accumulation level of the materials in the furnace be kept uniform throughout the circumferential direction of the furnace. In other words, coke and iron ore (including sintered ore) are alternately charged into the furnace in a fault-like manner in several stages.
The lower layer is gradually melted.

The accumulation level of the charge in the furnace changes due to changes in the profile of the lower part of the furnace, abnormal descent of the charge (slip), the appearance of tap slag, and the like.

Therefore, the balance of the deposition level of the contents in the furnace may be lost. For example, as shown in Figure 7,
In contrast to the normal deposition level in the blast furnace 1 shown by the dotted line B', as shown by the solid line B, there is an installation in which one side is near the vertical furnace mouth part 11 and the other part is in the shaft part 12 expanding downward. Container 2 becomes unbalanced. As a result, a large amount of hot gas flows toward areas with low deposition levels, causing equipment damage and
Problems such as unstable production and poor furnace heating occur.

If raw materials are charged in the unbalanced deposition state described above, the distribution and particle size of ore/coke in the radial direction will be different, which will exacerbate the unbalanced deposition level and cause the furnace to fail even if the raw materials and other operating specifications are changed. Not only is it difficult to turn the heat around, but it actually worsens the heat, and its stability is severely impaired. Moreover, it is difficult to correct the imbalance once it has occurred, and this tendency is further exacerbated, further reducing the stability of the furnace. Therefore, how to balance the radial distribution of the charged raw material without exacerbating the imbalance caused by the circumstances in the lower part of the furnace is considered to be extremely important in blast furnace operation.

Therefore, it is not possible to measure the accumulation level of the raw material charged into the blast furnace and replenish the raw material when the measured value of the accumulation level becomes constant. The conventional method of charging raw materials into the furnace is
It is as follows. That is, a lower limit point at which replenishment of raw materials is required and an upper limit point at which further charging is prohibited are set in advance in the furnace. As a means for measuring the deposition level, a measuring device such as a measuring rod or a weight is used, and the deposition level is detected when the tip of the measuring device comes into contact with the surface of the charge. Using such a detection means, replenishment of raw materials is carried out in the following manner.

One direction is arbitrarily specified in the radial direction in the furnace from the core of the blast furnace toward the furnace periphery, and at least one measurement point is set at the level of this specified direction. Then, monitor the measurement value of the deposition level at the set measurement point,
When the measured value reaches the lower limit of the preset deposition level, the raw material is replenished.

The in-furnace radial direction from the core of the blast furnace toward the furnace periphery is designated arbitrarily, for example, in two directions, and at least one measurement point is set at each designated direction level. Then, the measured value of the deposition level at each set measurement point is monitored, and when the measured values of the levels in the two designated directions all reach the lower limit of the preset deposition level, replenishment of the raw material is performed.

FIG. 5A shows the charging timing in the case of the above method, and FIG. 5B shows the charging timing in the case of the above method. In FIG. 5A, the solid line f indicates the specified direction level, and the dotted line g indicates the other direction level.
Further, in FIG. 5B, a solid line f indicates one specified direction level, and a dotted line g indicates the other specified direction level.

In the above-mentioned method, the above-mentioned unbalance cannot be resolved appropriately because the replenishment of the raw material is carried out based on the measurement value of the accumulation level only at the measurement point of the specified direction level in one direction. Furthermore, in the above method, when all the measured values at the measurement points in the designated direction levels in two directions reach the lower limit point, that is, when the deposition level C shown in FIG. Therefore, as shown in the figure, the charge 2
The raw material will be charged when the deposition level of is significantly lower than its lower limit point D. As a result,
The deposition level after charging becomes C', and the unbalance of the deposition level cannot be properly resolved.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional method and to raise the level of deposits during charging of raw materials to the same level as possible throughout the circumferential direction of the furnace, thereby preventing unbalance in the furnace. The object of the present invention is to provide a raw material charging method.

The method of the present invention specifies at least two mutually opposing radial directions in the furnace from the core of the blast furnace toward the furnace periphery, and at least two mutually opposing directions.
One or more measurement points are set on each of the direction lines of the direction, and a lower limit point and an upper limit point of the raw material accumulation level in the blast furnace are set respectively, and each of the specified points is set on each of the direction lines in at least two opposite directions. Continuously measure the accumulation level of the charged raw material at the measurement points, and start replenishment charging of the raw material when it is detected that the measured value at any one of the measurement points has reached the lower limit point. , and the replenishment of the raw material is terminated when the measured value at any one of the measurement points reaches the upper limit point.

In this invention method, as shown in FIG. 4, the radial direction within the reactor from the core toward the core periphery is specified at least in two opposing directions, for example, line a-b and line a-c. Then, a measurement point x is set on line a-b and a measurement point y is set on line a-c, and the deposition level is measured at each measurement point x and y by a known means. The above-mentioned designation of the radial direction inside the furnace is preferably four directions with an angular difference of 90°, such as north, south, east, and west.
It is desirable to set one or more measurement points on each direction line as many as possible. When two or more measurement points are provided on each direction line, the height of the measurement points gradually increases from the core toward the circumferential direction.

As shown in FIG. 3, a level lower limit point D and a level upper limit point U are respectively set in order to define a range in which the accumulation level of the charge 2 in the blast furnace 1 is kept constant. The lower level point D is set at the upper region of the shaft portion 12 of the blast furnace 1 or the furnace mouth portion 11, as shown in FIG. 3, and the upper limit point U is set at the upper portion of the furnace mouth portion 11. The upper limit point U is set at a position that does not interfere with the opening/closing operation of the bell 13 or the rotating operation of the swing chute (not shown). In addition,
In FIG. 3, 14 is a level measuring device.

The reason for providing the upper level limit point and the lower level limit point is to prevent the accumulation level of the charge from becoming too high and make it impossible to open/close the bell or rotate the chute; When the level becomes too low, the temperature of the gas discharged outside the furnace increases,
This is to prevent problems such as damage to equipment and reduction in production volume.

Measurement points x and a-c on line a-b mentioned above
When the deposition levels at both measurement points y on the line are measured and one of the measurement values reaches the lower level limit point, for example, as shown in FIG. 3, the measurement point x reaches the lower level limit point D. At that time, replenishment of raw materials is carried out.

FIG. 1 shows the charging timing according to the method of the present invention. In FIG. 1, a solid line d indicates the measurement result at point x of one specified level (line a-b) shown in FIG. The measurement results at the y point of the line) are shown.

As a result, as shown in FIG. 2, replenishment of the raw material is carried out at a time when the accumulation level A of the charge 2 does not fall much below its lower limit point D. In this way, as the raw material in the furnace accumulates, the rate of level increase in the higher portions is less than the rate of level increase in the lower portions due to the balancing effect of the raw materials flowing from higher to lower. As a result, as shown in FIG. 2, the deposition level A' after charging becomes approximately normal, and the imbalance in the deposition level is eliminated.

As the raw material charging progresses, the deposition level of the charged material increases sequentially and reaches the level upper limit point U shown in FIG. 3, for example, at the highest point in the deposition level, i.e., point x' in FIG. 3. Charging is stopped when it reaches the upper limit point U.

In the charging process, it is thought that the level increases more and more in the higher direction, but in the present invention, since the control is not based on the specified direction level, segregation is not promoted as in the conventional method, but rather it is eliminated. I will work in that direction. Then, as the deposition progresses, a self-balancing effect occurs in which the water flows from the higher side to the lower side, so that the level increase rate in the high part is suppressed to a small level compared to the level increase rate in the low part.

According to the method of the present invention, this is detected prior to the point in time when the deposition form of the materials in the furnace is likely to change significantly, and this point is set as the charging time. The charging balance can be stabilized, the discharge of unused gas can be reduced compared to the conventional method, and stable blast furnace operation can be performed. For example, when using the conventional method, the average level difference in four measurement directions (one measurement point in each direction) was 900 mm, but it was reduced to 400 mm using the method of the present invention. You can force it.

In addition, according to the method of the present invention, the stability of the furnace can be significantly improved, especially when the ore/coke is small as in all-coke operation, the distribution of the charge in the furnace changes. The method of the present invention is extremely effective because it is simple and requires balancing the charging level. Furthermore, even in pellet multi-mixing operations, the distribution of the charge tends to change, and the method of the present invention is extremely effective in stabilizing the balance.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the raw material charging timing according to the method of this invention, Fig. 2 is an explanatory diagram showing the accumulation state of the raw material charged according to the method of this invention, and Fig. 3 is a diagram for explaining the method of this invention. A schematic vertical cross-sectional view of the upper part of the blast furnace, Fig. 4 is a schematic cross-sectional view of the blast furnace showing an example of designated direction levels and measurement points, Fig. 5 A and B are diagrams showing conventional raw material charging timing, Fig. 6 7 is an explanatory diagram showing the state of accumulation of raw materials charged by the conventional method.
The figure is an explanatory diagram showing an unbalanced accumulation state of charges. In the drawings, 1...blast furnace, 2...burden, 11...furnace mouth,
12...shaft section, 13...bell, 14...level measuring device.

Claims (1)

[Claims] 1. The inside radial direction from the core of the blast furnace toward the furnace periphery is
Specify at least two opposing directions, and set one or more measurement points on each of the specified at least two opposing directions; The accumulation level of the charged raw material is continuously measured at each measurement point on the designated at least two opposing direction lines, and the measurement value at any one of the measurement points is determined to be the lower limit. When it is detected that the point has been reached, replenishment of the raw material is started, and when the measured value at any one of the measurement points reaches the upper limit point, the replenishment of the raw material is finished. A method for charging raw materials in a blast furnace, characterized by the following.