JP2006265647A - Method for determining distribution state of charged material in blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for determining the distribution state of charged materials in a blast furnace by which the flowing-in behavior of the charged material charged into the blast furnace can surely be obtained to stabilize a furnace operation. <P>SOLUTION: After charging the charging materials of coke or ore into the blast furnace 10, gas temperatures at the furnace top of the blast furnace are measured with a plurality of setting thermometers on the furnace diameter direction at the furnace top of the blast furnace, and the flowing-in distributing state of the charged materials in the furnace diameter direction of the blast furnace 10 is judged by comparing the measured gas temperature pattern and the preset gas temperature pattern, in the furnace diameter direction at the furnace top of the blast furnace. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a method for determining a flow distribution state of a charge (coke or ore) charged in a blast furnace.

In blast furnace operation, ore and coke, which are iron sources, are charged from the top of the blast furnace, and the ore is heated and reduced by the high-temperature reducing gas rising from below, thereby forming a cohesive zone in the blast furnace. Is done. Since the cohesive zone is an important guideline for blast furnace operation, the distribution of the ore and coke charge charged from the top of the blast furnace is adjusted so that the shape and position of the cohesive zone are appropriate. Adjustments are being made.
As an adjustment method, there is a method of adjusting the charging position of ore and coke by operating a charging device composed of, for example, a movable armor or a rotating chute provided in the upper part of the blast furnace. In some cases, it is necessary to grasp the distribution state of the charge charged in advance.
For example, Patent Document 1 collects temperature data from a plurality of thermometers provided on the furnace wall at the top of the furnace, uses the highest and lowest points of the temperature in each batch, and the flow behavior of the furnace interior contents from the difference. A method for detecting and controlling the charging device based on the detected value is disclosed.

Japanese Patent Laid-Open No. 8-35003

However, the conventional method still has the following problems to be solved.
Although the highest and lowest temperature points in each batch are used to grasp the flow behavior of the charge, there is a problem that the specific flow behavior of the charge in the furnace radial direction cannot be clearly obtained. there were.
In addition, the temperature data of the upper part of the furnace is an average temperature in the furnace radial direction, and the flow behavior across the furnace radial direction can be clearly obtained only by detecting the flow around the center in the furnace radial direction. There was also a problem that could not be done.
For this reason, blast furnace operation could not be performed stably.

The present invention has been made in view of such circumstances, can accurately obtain the flow behavior of the charge charged to the blast furnace, and can determine the charge distribution state of the blast furnace that can stably perform the blast furnace operation. It aims to provide a method.

The method for determining the charge distribution state of the blast furnace according to the present invention in accordance with the above object is to charge the gas temperature at the top of the blast furnace after charging the coke or ore charge into the blast furnace. Measured by a plurality of thermometers installed in the furnace radial direction, and compares the measured gas temperature pattern in the furnace radial direction at the top of the blast furnace furnace with a preset gas temperature pattern in the furnace radial direction of the blast furnace. The flow distribution state of the charge is determined.
Here, the preset gas temperature pattern is based on the minimum value of the gas temperature measured from when the charge is charged into the blast furnace during stable operation until the charge flows into the furnace. It means the regression curve of the temperature formed.

According to the method for determining the charge distribution state of the blast furnace according to claim 1, the gas temperature at the top of the blast furnace is measured by a plurality of thermometers installed in the diameter direction of the top of the blast furnace, and the gas temperature pattern is set in advance. Compared with the gas temperature pattern, the flow distribution state of the charge in the blast furnace radial direction is judged, so the flow behavior in the furnace radial direction of the charge charged to the blast furnace can be accurately obtained, Blast furnace operation can be performed stably.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 (A) is a longitudinal sectional view of the top of the blast furnace to which the method of determining the charge distribution state of the blast furnace according to one embodiment of the present invention, and FIGS. FIG. 2 is an explanatory view showing a gas temperature pattern at the top, FIG. 2 is an explanatory view showing a transition of CO reduction efficiency when the method for determining a charge distribution state of a blast furnace according to an embodiment of the present invention is applied, and FIG. These are explanatory drawings of the top of the blast furnace to which the determination method is applied.

As shown in FIG. 1 (A) and FIG. 3, the method for determining the charge distribution state of the blast furnace according to one embodiment of the present invention is the same as that of the coke or ore charge charged in the blast furnace 10. This is a method for determining the inflow distribution state and stably performing the blast furnace operation.
First, after describing the blast furnace 10 to which the method for determining a charge distribution state of a blast furnace according to an embodiment of the present invention is applied, the determination method will be described.

At the top of the blast furnace furnace, a large bell 12 for charging the charge into the furnace 11 is provided. In addition, on the furnace wall 13 below the large bell 12, a plurality of (herein, 24) movable armor (hereinafter also simply referred to as MA) 14 which are charging devices for charging materials are substantially provided along the circumferential direction. It is installed at equal intervals. The MA 14 has a configuration in which the shaft portion 15 is an axis and the guide plate 16 is tilted toward the furnace wall 13 or the large bell 12 side. The tilt angle α (for example, about 60 degrees or more and 90 degrees or less). ) Can be adjusted to cause the charge that has fallen along the large bell 12 to flow into the intended distribution state.

Here, when adjusting the MA 14, the guide plate 16 is moved to the furnace wall 13 side or the large bell 12 side by one notch (for example, one notch is not less than 0.5 degrees and not more than 2 degrees) for each charge. However, it is also possible to incline with the number of notches of 2 or more. At this time, a state where the upper surface 17 of the guide plate 16 of the MA 14 is not tilted, that is, a vertical state is defined as 0 notch. In addition, it means that the inclination | tilt angle (alpha) of the guide plate 16 is so large that the number of notches of MA14 is large.

Further, as shown in FIG. 1A, below the MA 14 in the furnace 11, a plurality (for example, two in this case) of water-cooled sondes 18 are directed from the furnace wall 13 toward the center of the furnace 11. It is charged radially. Each of the sondes 18 is provided with a plurality of thermometer-type thermocouples (hereinafter also simply referred to as thermocouples). Each thermocouple tip 19 protrudes from the bottom of each sonde 18 and is installed at substantially equal intervals in the longitudinal direction.
Here, the thermocouple tip 19 is a position where the charge is not buried even when the charge is charged to the furnace 11 as much as possible, and is preferably as low as possible, for example, the shortest distance from the charge. Is fixed at a position where it is about 50 mm or more and 500 mm or less.

Then, the determination method of the charge distribution state of the blast furnace which concerns on one embodiment of this invention is demonstrated.
As shown in FIG. 1 (A), charging of the charge into the blast furnace 10 is performed by dividing one batch of coke and ore into two parts, C1 (first layer coke) and C2 (second layer coke). ), O1 (first layer ore), and O2 (second layer ore) in this order, and this is performed as one charge, and multiple charges are performed continuously or intermittently.
As a result, coke and ore layers are alternately formed in the furnace 11.

Here, the gas temperature measured by the sonde 18 will be described.
One thermocouple for measuring the gas temperature is provided in the center of the furnace 11 and five in the furnace radial direction around the center, that is, a total of 11 thermocouples in the diameter direction of the blast furnace 10. FIG. 1B shows a gas temperature pattern of O1, and FIG. 1C shows a gas temperature pattern of O2.
The temperature pattern b in FIGS. 1B and 1C is the gas temperature pattern after the MA14 is adjusted to 4 notches and the first layer ore (O1) is charged, and further, the MA14 is 12 notches. It is a gas temperature pattern after charging to 2nd layer ore (O2).
This is to examine the gas temperature for ores that have a large change in the flow into the furnace and have a large impact on operations.

It should be noted that whether or not the flow distribution state of the charged ore is appropriate is determined based on the gas temperature pattern a set in advance in FIGS. 1B and 1C, that is, the first layer during the stable operation described above. The gas temperature pattern measured when ore (O1) was charged into the blast furnace 10, and when the first layer ore (O1) and the second layer ore (O2) were charged into the blast furnace 10 respectively. The measurement is performed by comparing with the measured gas temperature pattern b.
Here, the gas temperature pattern a and the gas temperature pattern b may be regression curves of temperatures formed based on the gas temperatures measured by the sonde 18 and sent to a control unit (not shown).

As shown in FIGS. 1 (B) and (C), the center of the furnace 11, that is, the thermocouple No. 5-No. The temperature measured in 7 is the thermocouple no. 1-No. 4 and no. 8-No. It can be seen that the temperature is higher than the temperature measured at 11. Furthermore, thermocouple No. 5-No. 7 was measured when the first layer of ore (O1) was charged and then the second layer of ore (O2) was charged. 5 and no. The temperature measured at 6 increased, and the thermocouple no. The temperatures measured in 7 are substantially the same.

Normally, when ore is charged, the gas temperature decreases. However, the fact that the gas temperature is increased in this way indicates that the flow distribution state of the second-layer ore (O2) is inappropriate, that is, the guide of MA14 This means that the inclination angle α of the plate 16 is not appropriate.
In this way, it is possible to determine the flow distribution state of the ore in the blast furnace 10 radial direction.
At this time, when an index indicating whether or not the reduction reaction is proceeding effectively in the blast furnace 10, that is, CO reduction efficiency η _CO was examined, as shown in FIG. 2, η _CO changed around 48%, It was found that the reduction reaction in the blast furnace 10 did not proceed effectively.
The CO reduction efficiency η _CO is expressed by the following formula.
η _CO = (CO ₂ ) / (CO ₂ + CO)

From the above, it is determined that the inflow distribution state of the ore is inappropriate. Therefore, in order to change the flow distribution state of the ore, the inclination angle α of the guide plate 16 of the MA 14 when the second ore (O2) is charged is changed from the next charge. As an example of the change in the inclination angle α, MA14 was adjusted to 13 notches (12 notches until the previous time) when charging the second layer of ore (O2).

Then, as described above, see the course of the comparison and CO reduction efficiency eta _CO transition between the gas temperature pattern b and the measured gas temperature pattern a previously set.
As a result, the temperature pattern b after charging the second layer of ore (O2) gradually approaches the temperature pattern a and becomes as shown in FIG. 1 (D). Further, as shown in FIG. efficiency eta _CO is gradually improved, it can be determined that can progress effectively the reduction reaction in the blast furnace 10. For this reason, the number of notches of the MA 14 is continued. If the temperature pattern b does not approach the temperature pattern a sequentially and it is determined that the reduction reaction cannot proceed effectively, the MA 14 is increased again (14 notches), and the same method as described above is used. The method is followed, and in some cases, the number of notches of the MA 14 is further increased and the subsequent process is observed.

As shown in FIG. 1 (E), the thermocouple no. 5-No. When the temperature measured in 7 is lower than the preset gas temperature pattern a, it is determined that the inflow distribution state of the second-layer ore (O2) is inappropriate. Therefore, in order to change the flow distribution state of the ore, the MA14 at the time of charging the second layer ore (O2) from the next charge is adjusted to decrease from 14 notches to 13 notches to adjust the second layer ore (O2). Was loaded.
As a result, the temperature pattern b after charging the second layer of ore (O2) gradually approached the temperature pattern a, and the furnace condition was stabilized.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included. For example, the right scope of the present invention also includes the case where the method for determining the charge distribution state of the blast furnace according to the present invention is configured by combining some or all of the above-described embodiments and modifications.
In the above embodiment, the case where the inclination angle of the MA guide plate is adjusted based on the gas temperature pattern when ores that are likely to change in the flow-in state are charged into the blast furnace has been described. In the case of charging, the inclination angle of the MA guide plate can be adjusted based on the gas temperature pattern.

(A) is a longitudinal cross-sectional view of the top of the blast furnace to which the method for determining a charge distribution state of the blast furnace according to an embodiment of the present invention is applied, and (B) to (E) are gas temperatures at the top of the blast furnace, respectively. It is explanatory drawing which shows a pattern. It is explanatory drawing which shows transition of CO reduction | restoration efficiency at the time of applying the determination method of the charge distribution state of the blast furnace which concerns on one embodiment of this invention. It is explanatory drawing of the blast furnace top part to which the same determination method is applied.

Explanation of symbols

10: Blast furnace, 11: Inside the furnace, 12: Large bell, 13: Furnace wall, 14: Moveable armor, 15: Shaft, 16: Guide plate, 17: Top surface, 18: Sonde, 19: Thermocouple tip

Claims (1)

After charging the coke or ore charge into the blast furnace, the gas temperature at the top of the blast furnace is measured by a plurality of thermometers installed in the diameter direction of the top of the blast furnace, and the measured blast furnace A blast furnace charging characterized by determining a flow distribution state of the charge in the furnace radial direction of the blast furnace by comparing a gas temperature pattern in the top furnace radial direction with a preset gas temperature pattern Judgment method of object distribution state.

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