JPS61266508A - Raw material charging method to blast furnace - Google Patents

Abstract

PURPOSE:To maintain the specified time series grain size pattern between batches with ease and good accuracy in an actual operation by measuring the grain size pattern of the raw materials charged into a blast furnace with time and adjusting the grain size pattern of the raw material of the succeeding batch with the deviation from the intended grain size pattern. CONSTITUTION:The charging raw material 2-1 distributed from a moving chute 1 is stored in a hopper 3. The grain size pattern of the charging raw material 2-2 for one batch which is successively arranged on a belt conveyor 5 can be adjusted by changing the angle theta of a movable type baffle plate 4. The material 2-2 is charged through a hopper in the top part into the furnace by a swiveling chute 17 in the furnace. The grain size pattern of the material 2-2 with time is measured, for example, by an acoustic type grain size meter 15 for the raw material provided to a vertical chute and the deviation from the target grain size pattern in the predetermined measuring position is determined. The grain size pattern of the raw material for the succeeding batch is so adjusted to attain the target pattern from the information on such deviation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates in particular to a method for adjusting the charge distribution when charging raw materials for a blast furnace.

(Prior Art) When charging raw materials into a blast furnace, many attempts have been made by countries in the United States and the United States to try to obtain suitable rolling conditions while adjusting the particle size of the charged materials.

For example, Japanese Patent Application Laid-Open No. 58-136704 discloses a technical means of actively adjusting the material accumulation state in the furnace top bunker as a charging method to obtain the optimum particle size distribution in the radial direction of the furnace depending on the inside situation of the furnace. has been done. That is, this case is based on the technical idea of maintaining favorable furnace conditions by actively changing the particle size pattern of the charged material according to the furnace conditions.

Furthermore, Japanese Patent Laid-Open No. 56-108808 also discloses a technique of actively changing the particle size distribution, similar to the above-mentioned publication.

(Problems to be solved by the invention) However, although these are all theoretically effective techniques, they are too complicated as control means in actual operation.
The problem is that it cannot be controlled according to theory. *Ta,
Not only that, there are more items to handle for operators,
Another disadvantage is that the operational load increases.

Therefore, the present invention provides a means for controlling raw material charging by particle size pattern adjustment, which avoids the difficulties of the above-mentioned means, is easy in actual operation, and has excellent accuracy and effectiveness.

(Means for Solving the Problems) The gist of the present invention is to measure the particle size pattern over time of the raw material charged into the furnace from the charging belt conveyor via the furnace top hopper and into the furnace by the furnace rotating chute. , find the deviation from the target particle size pattern at the predetermined measurement position, and charge the raw material into the furnace by adjusting the raw material particle size pattern of the next batch to match the target particle size pattern based on the deviation information. This is a method for charging raw materials into a blast furnace, which is characterized by keeping the time-series particle size pattern constant from batch to batch.

Measurements of the particle size pattern of the feedstock over time can be made at the head of the conveyor and/or at a location intermediate the furnace top hopper and the furnace rotating shade.

In addition, the particle size pattern of the raw material can be adjusted by operating the movable baffle plate installed in the Sarno hopper, and/or by adjusting the angle of the movable collision plate of the upper rotating chute installed above the top hopper or the tilting of the rotating chute. This can be done by manipulating the angle.

It is generally believed that there is a close relationship between the operational performance of a blast furnace and the charge distribution, and this has been determined by pattern recognition of the temperature distribution or gas utilization rate distribution in the blast furnace radial direction observed with a sonde. However, as a result of more in-depth research conducted by the present inventors, it was found that the operating performance of a blast furnace has a very large phase difference due to the degree of variation in the soot flow distribution between batches, rather than these patterns themselves.

Figure 2 shows the sonde measurement results of the blast furnace gas utilization rate over a certain period of time. A is fuel ratio when running smoothly = 47
Although it is low at 0 kg/l, the fuel ratio is 50 during poor operation.
It is 0 kg/l. Comparing the good times (A) and the bad times (A), the dispersion in the gas utilization rate during the good times (A) was 1.9%, while the dispersion in the bad times (A) was as large as 3.4%. 8. If we look at this point from another perspective, as shown in Figure 3(a), when the dispersion of the gas utilization rate increases, the
1 amount increases, or the shaft efficiency deteriorates as shown in FIG. 3(b).

Therefore, from these data, it was found that it is important to reduce the variation in the charge distribution between batches in order to reduce the variation in gas flow distribution and gas utilization rate.

No matter how constant the operating conditions are, the particle size pattern of the raw material on the charging belt conveyor over time in the direction of belt movement, that is, when it is charged from the belt to the top hopper, varies greatly from batch to batch. As a result, variations occur in the distribution within the furnace. For example, Fig. 4(b) shows the particle size measurement results obtained by sampling the charges on the charging belt conveyor in chronological order for three consecutive batches of 7- to 7-year-olds as shown in Fig. 4(a). As you can see.

Therefore, in the present invention, based on the above knowledge, we focused on the fact that it is sufficient to control the particle size pattern of the charge particles distributed in the furnace to be constant between each batch.

(Function, Examples) Hereinafter, the function of the present invention will be specifically explained based on Examples.

FIG. 1 is an overall conceptual diagram showing the implementation status of the present invention.

The charged raw material 2-1 distributed from the moving chute 1 is stored in the surge hopper 3. At this time, surge hopper 3
By changing the angle θ of the movable baffle plate 4 disposed inside, it is possible to adjust the particle size pattern of one batch of charging raw materials 2-2 arranged over time on the charging belt conveyor 5. It ends with

This one-batch raw material 2-2 is charged from the head 5' of the charging belt conveyor 5 to the upper revolving shade 7 provided above the upper hopper 9, and one batch is deposited in the state 2-3. The raw material 2-4 is charged and distributed through the lower hopper 12 and the vertical chute 16 by the in-furnace rotating chute 17.

In addition, as another method for adjusting the particle size pattern, the inside of the upper hopper 9 can be adjusted by adjusting the angle φ of the movable collision plate 8 of the upper rotating chute 7 or by adjusting the tilting angle of the upper rotating chute 7. A desired particle size pattern can be formed by changing the deposition state of the charged raw material 2-3.

By selecting or combining both of the above means, the accumulated particle size distribution state of the charged raw material 2-4 finally charged by the in-furnace rotating chute 17 is made relatively constant between each batch.

As a means for measuring the particle size pattern of each batch, for example, a furnace top raw material particle size measuring device 6 with an image processing function installed near the bottom trs5' of the charging belt conveyor 5, or Inner rotation chute 1
7, for example, vertical chute 1.
It is also possible to measure using the acoustic, vibration, or microwave type raw material particle size meter 15 provided at 6.

Based on this measurement information, a change in particle size over time at a measurement position, that is, a particle size pattern is detected online.

On the other hand, as a method of determining a target particle size pattern in advance before online measurement, for example, to make the particle size pattern constant between batches when charging from the charging belt conveyor 5 to the top of the furnace, it is possible to A time-series particle size pattern is stored in advance in the calculator 18 based on the relationship between the angle α of the upward-sloping characteristic shown in FIG. 5 and the angle θ of the movable baffle plate 4 in the surge hopper 3, and the target particle size pattern is The required control amount Δθ (=a1・Δ
α) can be computationally controlled. As a result, the particle size pattern of the raw material charged from the charging belt conveyor 5 to the top of the furnace is constant for each batch, which causes the upper hopper 9
The particle size pattern of the raw material discharged from the lower hopper 12° through the in-furnace rotating chute 17 is also constant for each batch.

Another method for making the raw material particle size pattern from the in-furnace rotating chute 17 constant is to change the particle size pattern detected by the raw material particle size meter 15 to the right-sloping characteristic angle β shown in FIG. In relation to the angle φ of the plate 8, past several batches are stored in advance in the calculator 18, and the necessary control amount Δφ of the angle φ of the movable collision plate 8 in the next batch is determined from the deviation Δβ from the particle size pattern of the @ mark. By calculating and controlling (=l), ·Δβ), the particle size pattern of the raw material discharged from the in-furnace rotating chute 17 can be made constant for each batch.

As the furnace top raw material particle size measuring device 6 for online measurement of particle size, it is suitable to use a method using image analysis, a method using sound or vibration, or a method using a microwave sensor. The raw material particle size meter 15 installed between the two is a device using an acoustic or vibration method, or a method using a microwave sensor. The equipment is suitable.

FIG. 9 shows an example of the results of particle size measurement conducted by the present inventors. Figure 9(a) shows the acoustic measurements taken at the charging belt conveyor head of an actual furnace and the correlation with the sampling results on the belt. The correlation between the particle size of the raw material estimated from the microwave intensity and the particle size of the supplied sample was taken using a ball as a sample. Both have good correlation within an error of ±211 m, and can be put to practical use as an on-fin particle size meter.

In order to confirm the effects of the present invention, a test was conducted by changing the particle size structure of the raw material and charging it into a circ hopper. As a result, as shown in Figure 10 (,), when the baffle plate angle is set to a constant angle (=0°), the particle size patterns of the three types of raw materials vary greatly, but if the baffle plate angle is selected excessively, For example, data with reduced variation was obtained as shown in FIG. 10(b).

(Effects of the Invention) As described above, controlling so that the particle size pattern of each batch measured online at a predetermined position matches a predetermined target particle size pattern for each batch is not only easy as a control method, but also Since there is no need for operators to consider the effects of fluctuations in raw material conditions, this method is actually extremely effective for charging raw materials into a blast furnace. Changes in the bus flow distribution become extremely small, improving the operational performance of the blast furnace.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the concept of implementing the method of the present invention, Figure 2 is a diagram showing the radial gas utilization rate distribution measured with a shaft sonde of a blast furnace, and Figure 3 b) is a diagram showing the distribution of gas utilization rate in the radial direction measured with a shaft sonde of a blast furnace. Relationship between variation in radial gas utilization rate distribution and blast furnace pig iron [Sil,
Figure 4 (b) is a diagram showing the relationship between variations in the gas utilization rate distribution and shaft efficiency, which represents the reduction efficiency of the blast furnace. Figure 4 is a diagram showing the raw material particle size distribution over time on the charging belt conveyor in an actual furnace. Figure 5 shows the raw material particle size pattern over time when the raw material is supplied from the charging belt to the furnace top, and Figure 6 shows the relationship between the raw material particle size pattern angle and the angle of the movable baffle plate in the surge hopper. Figure 7 is a diagram showing the discharge pattern over time of the raw material when it is charged into the furnace from the furnace chute, and Figure 8 is a diagram showing the relationship between the raw material particle size pattern angle and the upper rotating chute collision plate angle. , Figure 9 is a diagram showing the results of an online particle size measurement test conducted by the present inventors, Figure 10 is a diagram showing raw material discharge patterns when different raw materials are charged into the surge hopper, and (a) of the same figure is a diagram showing the results of an online particle size measurement test conducted by the present inventors. When the movable baffle plate in the hopper is not adjusted, FIG. 6B is a diagram showing the case where the movable baffle plate is adjusted.

Claims (6)

[Claims] (1) Measure the particle size pattern over time of the raw material charged into the furnace from the charging belt conveyor via the furnace top hopper and into the furnace by the in-furnace rotating chute, and compare it with the target particle size pattern at the predetermined measurement position. By determining the deviation and adjusting the raw material particle size pattern of the next batch to match the target particle size pattern based on the deviation information, the time-series particle size pattern when charging the raw material into the furnace is made constant between batches. A method for charging raw materials into a blast furnace characterized by the following. (2) The method according to claim 1, wherein the particle size pattern of the raw material over time is measured at the head of a conveyor. (3) The method according to claim 1 or 2, wherein the particle size pattern of the raw material over time is measured at an intermediate position between the furnace top hopper and the furnace rotating chute. (4) The method according to any one of claims 1 to 3, wherein the particle size pattern of the raw material is adjusted by operating a movable baffle plate provided in a surge hopper. (5) The particle size pattern of the raw material is adjusted by manipulating the angle of a movable collision plate of an upper rotating chute provided above the furnace top hopper. the method of. (6) The method according to any one of claims 1 to 4, wherein the particle size pattern of the raw material is adjusted by manipulating the tilt angle of an upper rotating chute provided above the furnace top hopper.