JPS6041121B2 - Material charging method for bellless blast furnace - Google Patents

Description

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

Controlling the charge distribution in blast furnace operation plays a very important role in maintaining stable furnace conditions.

Recently, large bell-less blast furnaces have been increasing in various places.Compared to bell-type blast furnaces, they have the advantage of being able to charge anywhere in the furnace, making it easier to control the burden distribution. Being present is a big factor. Figure 1 shows a diagram of the bellless bagging device. The ore 2 and coke 3 stored in the furnace bunker B are sequentially cut out, received in a rotating chute 4 provided at the top of the furnace, and set at an arbitrary moving angle 8 and number of turns N.
By distributing ore, coke, etc. to arbitrary parts of the top charge surface, the furnace condition of the blast furnace is maintained in an optimal state. In the operation of such a bellless blast furnace, a more important issue is how to maintain the gas flow distribution within the furnace in an appropriate state and how to efficiently utilize the sensible heat and reducing ability of the gas. That is,
The gas flow distribution in the blast furnace should be such that sufficient contact between the gas and the charges such as coke, ore, etc. is achieved, and heating and reduction occur. It is desirable to have a flow distribution. In FIGS. 2A, B, and C, high-temperature air blown into the furnace from the blade □16 of the blast furnace 1 reacts with the coke 3 to produce C○, ratio,
Furthermore, this C○, ratio reduces ore 2 to C02, day 20
This generates gas, which eventually becomes furnace top gas and is discharged outside the furnace.

Here, the gas flow distribution in the furnace is typically determined by the distribution of the coke 3 and the bags such as ore 2 as shown in Figures A and B.
It is classified into three forms 5A, 5B, and 5C shown in C.
In FIG. 2A, more coke 3 with excellent air permeability is charged in the furnace center 13 than in the furnace wall, and as a result, there is a large gas flow in the furnace center 13, and a gas flow in the furnace wall 14. The internal operations are somewhat oriented towards central flow. In this type of internal operation, the flow path of the gas flow is fixed, so there is little wind pressure fluctuation and the operation is very stable. However, because the blast furnace is used in a narrow space, productivity and efficiency are poor, and it is extremely difficult to operate. In such a case, the ore on the down side of the reactor will hardly be reduced and will fall unmolten into the vane, potentially causing serious accidents such as vane collapse. In the case of FIG. 2B, more coke 3 is packed in the furnace wall 14 than in the furnace center 13, and as a result, there is a large gas flow in the furnace wall 14, and a small gas flow in the furnace center 13. This is an external operation oriented toward so-called furnace wall flow.

In such external operations, blast furnaces are used extensively, which improves efficiency, but the gas flow path is unstable and wind pressure fluctuations become severe. Moreover, in the case of this external operation, since the furnace wall is normally cooled using cooling water to protect it, the amount of heat carried away by the cooling water and the heat dissipated increase, which is not desirable in terms of energy saving. Particularly in cases where there is significant external operation, the heat load on the furnace body becomes large, which may cause damage to the furnace wall or molten ore to melt the tuyere, leading to damage. Figure 2C
is located between internal operation and external operation, and indicates the so-called optimal operating state oriented toward intermediate flow, in which the gas flow distribution within the furnace is appropriate.

Therefore, blast furnace operators adjust the radial distribution of coke 3 and ore 2 in the blast furnace 1 through trial and error to obtain an appropriate gas flow distribution state as shown in FIG. 2C. Here, there is still no practical method to directly detect the gas flow distribution in the furnace, and generally the radial gas composition distribution measured by a shaft probe 6 as shown in FIG. The gas flow distribution in the furnace is estimated based on the radial gas temperature distribution measured by the furnace top fixed temperature probe 7 or the furnace body heat load based on the thermometer embedded in the stave.

That is, the shaft sonde 6 is inserted into the furnace contents layer while moving in the radial direction, and the gas is sampled at its tip, and its composition is measured by the analyzer 8.

This shaft probe 6 often stops at several points in the furnace and measures each composition at a constantly determined position. There are various methods for processing the gas composition value, but the CO component C○i, C02 component, and C02i in each layer i in the radial direction of the furnace are measured, and the gas utilization rate C in each layer is measured.
○i, C02i CCM=C.

2i+C.

A method of calculating by i is generally used.

On the other hand, the furnace top fixed temperature probe 7 is fixed above the raw material in the furnace and measures the temperature distribution of the gas flow using thermocouples installed at several points in the radial direction.
Output signals from the shaft sonde 6, furnace top fixed temperature sonde 7, etc. are processed by a process computer 9, displayed on a display device 10, and stored in a storage device 11. On the other hand, the gas flow distribution in the furnace is controlled by adjusting the distribution of coke and ore charges in the radial direction, and in the bellless type blast furnace shown in FIG. This is achieved by adjusting the rotation of the swing chute 4 and the loading angle using the charging control device 15.

The conventional charging method using a rotating chute in this case, taking ore as an example, as shown in Table 1, displays a movement angle of 0 as a position for each number of turns N of the rotating chute 4 and creates a pattern. This is done by setting this position according to the gas flow distribution.

Table 1 However, the measurement results of the blast furnace gas flow distribution mentioned above are
It is difficult to quantify the pattern information as shown in the figure.

Therefore, a gas distribution triangular diagram as shown in FIG. 3 has conventionally been used as a method of summarizing this information to understand the gas flow distribution in the furnace. This means that each vertex of an equilateral triangle is represented by, for example, point A at 100% intermediate flow, point B at 100% center flow, and point C at 100% furnace wall flow, and the gas flow distribution in the furnace at a certain operating level is expressed as described above. This diagram shows the current gas flow distribution form by dividing it into center flow, furnace wall flow, and intermediate flow based on information from temperature and gas detection sensors. For example, point D in the figure shows a gas distribution of 50% center flow, 20% furnace wall flow, and 30% intermediate flow. However, even if the current gas flow distribution form is displayed in this way, it is still difficult to properly control the distribution of bag contents by matching the bellless patterns shown in Table 1. While looking at the measurement results of the gas flow distribution and Figure 3 derived from those results, the operator selects the moving position for each charge of ore and coke according to the subjective opinion of the operator and the light weight regulations. Distribution is controlled.

For this reason, it has been difficult to maintain stable blast furnace operation at all times under the conventional technology. In this sense, although it is required that the gas flow distribution described above corresponds to the temperature distribution and the bellless pattern and that the charge distribution is always controlled appropriately, such technology has not yet been established. This is the actual situation. The purpose of the present invention is to solve the above-mentioned problems of the prior art in the method of charging raw materials using a bellless blast furnace having a rotating chute, and to grasp the gas flow according to the furnace conditions such as gas flow distribution and temperature distribution. The purpose of this invention is to provide a method of charging raw materials that can always ensure optimum furnace conditions by charging raw materials into the furnace by matching the charging method by controlling the rotating chute.

The details of the configuration of the method of the present invention will be explained below. The present invention is based on the knowledge from past blast furnace operation results that stable blast furnace operation can be maintained if the gas flow distribution can be sufficiently adjusted in two places: near the furnace wall and near the center of the furnace. This is the method that was perfected. In response to that knowledge, the present invention
The amount of ore and coke charged in one charge is divided into the first half and the second half, and the total number of revolutions of the distribution chute is also divided into the first half and the second half.For example, charging in the first half is divided into two parts: Assuming that the latter half of the charging contributes to the gas flow control from the middle part to the center of the furnace, a diagram of the charging pattern is created in which these gas flow distributions and the rhombus patterns correspond to each other. On the other hand, the charging and distribution of raw materials is controlled in relation to the control values of various information regarding furnace condition indicators such as gas flow distribution index, gas temperature, and furnace heat load obtained from various sensors. When setting the above-mentioned bagging pattern, gas flow distribution can be roughly divided into three types in the radial direction inside the furnace: center flow, intermediate flow, and furnace rectification. The gas flow distribution in the furnace is expressed as a furnace wall flow to a center flow. - is displayed to create a triangular diagram, and the setting position of the distribution chute according to the gas flow distribution form in the radial direction within the furnace is displayed or selected.

The setting position of the distribution chute set on the oblique side of the above triangular diagram is determined as follows.

In the 2-batch, 1-charge bag packaging format for the combination C and 0 as shown in Figure 4-a, there are first and second half bags for each of C and 0, while CC as shown in Figure 1-b. , 00 in a 4-batch 1-charge charging mode, it is divided into CC and 00 batches in advance,
In the case of CC, the first half contributes to the promotion or suppression of the furnace wall flow, and the second half contributes to the center flow, and in the case of 00, the first half contributes to the promotion or suppression of the furnace wall flow, and the second half contributes to the center flow. Allocate one charging charge according to the number of turns. For example, 1 of C in 2 batches of CO and 1 charge
For a batch, when distributing the number of turns in the furnace with 14 turns, as shown in Table 3, the first 1 to 6 turns contribute to the furnace wall flow, and the 10 to 14 turns contribute to the center flow. Set several patterns.

Regarding the remaining 7 to 9 turns, since the number of patterns is large and the degree of influence is small, we fixed them as one pattern for convenience and distributed the charge to either the front or the latter half as appropriate, but depending on the blast furnace volume or operating conditions. , preferably divided into two. Table 2 Table 3 In this way, several types of patterns set by combining the first half or second half turning doctrine with the forward angle of the distribution shot can also be used, for example, simply as shown in Table 2.
For something like a combination of numbers 3...
It is extremely inconvenient to discern at a glance where the shoot is located.

Therefore, in the present invention, for convenience, we first use the sine s as a charging distribution index.
Using the formula inG/N (where sin8=incline angle N=number of turns), the positions corresponding to the patterns (moving positions) shown in Table 3 from the center of the furnace are determined and arranged.
That is, taking pattern U in FIG. 3 as an example, if the inclination angle of turns 1 to 6 is represented by 112233, then 11...
sin5 is 22...sin50.5033
...sin48.50 Since N=6 turns, si
n520=Q, sin50.50=8sin48.50
If =y, then N2Sin8/N=QX20Bza20r+2=o-769
7i〒1Sin8/N=QX218honor20y+2=0.7697.

In this way, each pattern is similarly indexed and arranged in order of numerical value, as shown in Table 3. In addition, the tilting angle is 8, and the i-room. S
Table 4 shows the correspondence between in8/N.
Table 4 In Table 3, the g to z patterns on the left represent patterns from 1 to 6 turns, and the 2 to 27 patterns on the right represent 10 turns.
A pattern of ~14 turns is shown.

As it changes from g to z, the angle of motion increases, and when ore is charged, the ore is distributed closer to the furnace wall, suppressing the furnace wall flow and causing intermediate sulfidation, and conversely changing from z to g. In this case, the oscillation angle is 4.0 and the flow is distributed in the middle, suppressing the middle flow and creating a furnace wall flow pattern. On the other hand, as the pattern changes from 27 to 2, the deflection angle becomes larger, and when ore is inserted, the ore is distributed to the middle part, so the middle flow is suppressed and becomes a central flow, and conversely, from 2 to 27 When the flow changes to , the motion angle becomes small and the central part is distributed, suppressing the central flow and creating an intermediate sulfidation pattern.

In the case of coke charging, the gas flow form is exactly opposite to the above-mentioned ore example, but in any case, the pattern set in z~g, 2~27 is the middle-furnace wall, middle in the radial direction of the furnace. - It can be treated as representing the gas flow distribution at the center of the furnace. Furthermore, the above-mentioned pattern is displayed in correspondence with a center C-intermediate A-furnace wall B sulfidation diagram as shown in FIG.

That is, the hypotenuse AB has a pattern z determined by 1 to 6 turns.
~g, and patterns 26 to 2 determined by 10 to 14 turns are written at equal intervals on the hypotenuse AC. For example, by creating a triangular diagram as shown in Figure 5, the operation pattern can be set to n-23 (point C in Figure 5), P-16 (point
Point D in the figure) can be uniquely determined. This will be explained below using the example of ore cutting. Considering that the operation pattern has changed from point C to point D in Figure 5, the pattern of 1 to 6 turns changes to n or p, and the ore is distributed closer to the furnace wall, which reduces the furnace wall flow. It is a suppressed intermediate flow-oriented distribution control, and 10 to 14 turns are 23 → 1
By changing to 6, the ore is distributed to the middle part, indicating that the distribution control has changed to a center flow direction.

In short, in the pattern of p-16 (point D), more raw material is charged in the middle than in point C, so the middle flow is suppressed when ore is charged, and the gas is oriented towards middle flow when charging coke. It can be seen that the pattern is a rhombic pattern that controls the flow distribution. Furthermore, as the current gas flow distribution has shifted from point C to point D, it can be seen that it has become closer to a central flow as shown at the bottom. Therefore, the appropriate charging pattern can be easily selected for the next step. As explained above,
The control pattern of the rotating chute is selected according to the shape of the gas flow distribution, and control is performed so that the gas flow distribution is always optimal. However, it is not enough to select and control the charging pattern according to the shape of the gas flow distribution. Since sufficient gas flow distribution control is not possible, the present invention further quantifies the furnace condition index represented by the furnace body heat load, gas temperature, gas utilization rate, etc., which are closely related to the gas flow distribution form, and The feature is that the control value of the amount is predetermined by analyzing past data and used as an index for charging pattern selection in gas flow distribution control.

Here, the furnace heat load represents the value TL, which is the calorific value calculated from the heating state of the furnace shell obtained from the reading of the thermometer embedded in the staple. It is used to express strength and weakness.

Regarding the gas temperature, among the temperatures measured at six points at equal intervals in the radial direction inside the furnace with a fixed temperature sonde 7 as shown in Fig. 1,
This value is used as a control index because the difference between the two values (min) represents the strength of the furnace wall flow. Moreover, the gas utilization rate is C based on the gas composition at 10 points in the radial direction inside the furnace obtained by the shaft sonde 6 as shown in FIG. C02i C is determined by the formula of sukisaoi and convenient for use.

j+C. Gas utilization index expressed as 2i×18-3:
Use N.

In determining these control values, we determined the appropriate ranges based on an analysis of past blast furnace operation data.

First, regarding the furnace heat load TL, 600 x 1 pkca
In the case of more than 300
It has been found that if the control value T
L was set in the range of 300 to 600×1 and KCal/h. Similarly, regarding the gas temperature (T6 - Tm'n), past operation data shows that if [temperature T6 on the furnace wall side - minimum temperature Tm:n in the radial direction inside the furnace] is less than 20oo, the gas will flow to the furnace wall side. It was found that when the temperature exceeds 5000, a lot of gas flows toward the reactor wall, and the flow is directed toward the reactor downflow.
The control value was set in the range of 20oo to 50qo. Similarly, regarding the gas utilization rate index N', C.

2j C.

2i+C.

The smaller the value obtained by i×18-3, the stronger the gas flow can be considered, and among the 10 divided measurement points in the radial direction of the furnace, the measurement point N is on the down-side of the furnace. Since it is sufficient to select two values, ie, and the value of the measurement point N at the center of the furnace, as a control index, control values were determined for the measured values of the gas utilization index at these two points. In determining this, we analyzed past operational data and found that 1<N. <3. Fu 4<N. Since it was found that o<7, this was adopted as the control value for the gas utilization index N value. Next, Figure 6 shows a flowchart of the charging pattern selection method and charge distribution control based on the management values of the furnace heat load, gas temperature, and gas utilization index mentioned above.
FIG.

In other words, regarding the gas flow distribution form during the current operation displayed as the current pattern, whether it is center flow oriented or furnace wall flow oriented is determined in the order of furnace heat load, gas temperature, and gas utilization index N value. Let's compare. It is preferable to make a comprehensive judgment regarding these indices representative of the furnace condition, and to judge them in order from those that can be continuously measured, that is, those that are easy to grasp. For example, regarding the furnace heat load TL, the measured value is TL>600×1 pKCal/h,
And if the gas temperature is T6-Tmin>50q0,
This indicates that a large amount of gas is flowing toward the furnace wall, which cannot be said to be an appropriate distribution. For this reason, the pattern of 1st to 6th turns of ore is changed so that more ore is charged on the down side. That is, in the triangular diagram shown in FIG. 5, since the change is made in the direction g→z, the flow becomes as shown in the flow chart in FIG. 6, which is a direction parallel to the hypotenuse g→z. On the other hand, the furnace heat load TL is 300×
1 pi KCal/h or less, and the gas temperature is T6-T
If min<2000, this indicates that the gas flow on the furnace wall side is weak, and z→ in the triangular diagram shown in Figure 5.
It is necessary to change the pattern toward the g direction. This is a direction parallel to the hypotenuse z→g, as shown by ■ in the flow of FIG. In addition, the furnace heat load TL is 600 to 300 x 1
N, which indicates the strength of the central flow, even if it is between KCal/h
, is 1<N. <3.5, that is, N. If <1, the center flow is judged to be excessive, and the pattern must be changed to include more ore in the center. To do this, the hypotenuse 2→28 of the triangular diagram shown in Figure 5 must be changed. Change the pattern in the direction.

This is shown in case A in FIG. On the other hand, in the case of N>3.5, the pattern is changed in the direction 28→2, that is, case B in FIG. 7, for central flow control. Furthermore, N indicates the strength of the furnace wall flow. is 4<N,. <7, that is, N. In the case of <4, it is determined that the peripheral flow is excessive, and the action of case C in FIG. 7 is taken as in the case of the gas temperature T6-Tmin>50q0 described above. On the other hand, the gas temperature N, o>
7, it is judged that the peripheral flow is small, and the gas temperature t-Tm
As in the case of in<20oo, it is necessary to take the action of case D in FIG. When all of the above conditions are met, it is determined that the distribution control using the current pattern is appropriate, and the pattern is not changed, and the current status is instructed to be maintained as shown in the flowchart of FIG. 6.

In the present invention, the flow shown in FIG. 5 is processed by the process computer 9 shown in FIG. 1, and the pattern change figure shown in FIG.
It is displayed on the display device 10. Next, examples of the present invention will be described.

This example shows that the bellless charge distribution was adjusted according to the above pattern change conditions by applying it to an actual operation with a blast furnace volume of 4,500, an air flow rate of 600 side/min, and 0/C3.50. The results are shown in FIG.

However, the numerical values (3'1...) in the triangular diagram represent the date, and the moving arrows of the points represent the control process. Example 1 D point n-24 → E point m-24 During operation in the pattern of n-24, N,
is 1. Egg, o was 7.3.

In addition, the gas temperature T6-Tm,n measured with a fixed sonde is 40°C, and the furnace heat load TL is 4.5 million KCal/h.
The situation was as follows. Therefore, judging from the pattern change flow shown in Figure 6, 3 million KCal/h<heat load<60
00,000 KCal/h, 20℃<T6-T skin<50℃, 1
<N. <3.5 is satisfied, but N. >7.0, so it was necessary to change the pattern ◎. Therefore, we returned to Fig. 8 and adjusted the distribution by changing the pattern of turns 1 to 6 from n to m. As a result, the values of N and o decreased to 5.3 as shown in Fig. 12, and the appropriate We were able to secure distribution. Example 2 Point B ○-22 → Point C ○-21 The same blast furnace as in Example 1 was operated in the same manner.
In the pattern at point B, the furnace body heat load is 5.1 million KCal/h.
, the gas temperature T6-Tmin was 4200, N,o was 6.2, and N· was 3.6, as shown in FIG.

Judging from the pattern change flow shown in Figure 6, N, >
3.5, so it was necessary to change the pattern shown in Figure 6. In other words, the gas distribution suppresses the central flow, so 10
~ Pattern change 2 in which ore is charged into the middle part after 14 turns
2 → 21 was performed. As a result, as shown in Figure 10, N,
was reduced to 2.6, indicating an appropriate distribution. As explained above, according to the present invention, it is possible to easily display a charging pattern that takes into account the gas flow distribution form, and if the pattern can be easily selected, it is possible to easily display a charging pattern that takes into account the gas flow distribution form. The charging pattern can be easily selected and controlled based on the controlled values of the gas temperature, gas utilization rate, and furnace heat load, making it possible to always obtain an appropriate gas flow distribution in the furnace, resulting in stable blast furnace operation. can.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the bellless bagging device, Figure 2 A, B, C
is an explanatory diagram showing the relationship between typical gas distribution and ore and coke bagging conditions, Figure 3 is a diagram showing a triangular diagram of subordinate gas distribution, and Figure 4 a and b are typical charging diagrams. A line diagram showing the method, Fig. 5 is a ternary state diagram showing a triangular diagram based on the present invention of furnace wall-middle-center flow corresponding to the pattern, Fig. 6 is a flow diagram for changing the bellless pattern, Fig. 7
A to D in the figures are diagrams showing the relationship between pattern change conditions and triangular diagram display, Fig. 8 is a state diagram showing the transition during pattern change using the triangular diagram adopted in the present invention, and Fig. 9 is pattern ○-22. A diagram showing the relationship between the gas distribution and the fixed sonde temperature distribution in Figure 10 is pattern ○-21.
11 is a diagram showing the relationship between the gas distribution in pattern n-24 and the fixed sonde temperature distribution. FIG. 12 is a diagram showing the relationship between the gas distribution in pattern n-24 and the fixed sonde temperature distribution.
-24 is a pictorial diagram showing the relationship between gas distribution and fixed sonde temperature distribution. Figure 1 Figure 2 Figure 3 Figure 4 Figure 7 Figure 5 Figure 6 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12

Claims (1)

[Claims] 1. In the method of charging raw materials by adjusting the movement of the rotating chute based on the gas flow distribution in the furnace, the gas flow is first divided into center flow, intermediate flow, and wall flow with respect to the gas flow distribution in the furnace. After separating them, they are arranged at each apex angle of a triangle, and the combination of rotation number N and inclination angle θ is applied to the side between the center flow and the intermediate flow and the side between the furnace wall flow and the intermediate flow. A charging pattern display triangular diagram is created with the index of the rotating chute tilting position on a scale, and the current material distribution position is displayed on the triangular diagram.Based on the diagram display, the furnace heat load, gas temperature, and gas utilization are displayed. A material charging method for a bellless blast furnace is characterized in that the next charging pattern is determined in correspondence with the furnace condition index represented by the ratio, and charging is performed by adjusting the swing chute.