KR20010035940A - Charge control method having function for compensating level variation of charge in blast furnace - Google Patents

Abstract

PURPOSE: A charging control method is provided to constantly maintain burden distribution, thereby improving quality of hot metal discharged from a blast furnace and productivity and life cycle of the furnace by controlling speed after detecting a level of the charging material in the furnace. CONSTITUTION: The method comprises the steps of a first step of detecting a level of a charging material at furnace wall side along the circumferential direction; a second step checking whether or not a deviation of a maximum value and a minimum value of the detected level of charging material is within the set management range; a third step of calculating a volume inside the blast furnace which is required to recover an average level in the deviation compensation interval after dividing into a certain number of intervals, calculating a standard level and setting a deviation compensation interval; a fourth step of calculating a rotation speed of a rotation chute according to the amount after calculating an amount which is required to recover the average level; and a fifth step of charging as rotating the rotation chute only to the set standard speed when the level deviation of charging material is within the management range, and charging as changing the rotation speed to the standard speed in case of outside the deviation compensation interval and to the rotation speed for the calculated deviation compensation in case of inside the deviation compensation interval when the level deviation of charging material is not within the management range.

Description

CHARGE CONTROL METHOD HAVING FUNCTION FOR COMPENSATING LEVEL VARIATION OF CHARGE IN BLAST FURNACE}

The present invention, when charging the fuel and raw materials in the blast furnace (Blast Furnace), to maintain a constant circumferential charge level in the circumferential direction to reduce the aeration resistance of the bulk and soft fusion zone and to maintain a constant melt temperature in the direction of the furnace The charging control method in which the level deviation compensation of the blast furnace charge can be made.

In general, the blast furnace is to put iron ore and burn the coke to remove and dissolve the oxygen in the iron ore to make pig iron, in order to charge the coke as fuel and the iron ore as a raw material, as shown in Figure 1 10) Conveyor belt (5) for raw material loading inclined from the top to the ground is installed. In the upper part of the furnace, as a charging device for evenly distributing the raw material and inserting it into the blast furnace, turning, tilting with the top hopper (6) A plurality of measuring instruments including a swing shooter 8 for charging the lead / raw material of the top hopper (6) in the blast furnace 10, and measuring the pressure, temperature, components and the falling strength of the charged raw material in order to determine the blast furnace condition And many other devices.

At this time, the coke 1, the allied sintered light 185 and the small sintered light 13 are respectively stored in the hopper 4 located in the upper side of the ground side of the conveyor belt (5), a certain amount of the conveyor belt through the hopper (4) When discharged to (5), through the moving conveyor belt (5) coke, allied sintered light, small sintered light, etc. are stored in the hopper 6 in turn. In this way, when the lead / raw material of the appropriate level is stored in the top hopper (6), by turning and tilting the turning shooter 11 using the top charging device to charge the fuel, the iron ore and coke (charge) Cycles in order of coke, allele ore, and small iron ore) Each time it is charged, it tilts at a certain angle (ie, 60 °), and every six charges is rotated forward and reverse to 1.0. A coke terrace of ˜1.2 m is formed, and iron ore (also called ferros) is charged thereon to form a layer by the load of the charge.

Then, if the preheated air is blown into the tuyere 9 in the bottom of the blast furnace 10, the coke is burned by hot air to melt iron ore to form a molten iron.

Such blast furnace operation is economical only when the soft and raw material distribution in the blast furnace 10 is stabilized, the flow of iron is reduced and melted under favorable conditions, and the melt 14 collected at the bottom of the blast furnace is well discharged to the outside of the furnace. It is possible to carry out operations and to improve productivity and blast furnace life.

Therefore, coke is used as a fuel compared to other fuels, and even though coke is used as a fuel, as shown in FIG. 2 due to a failure of a top charging device, fluctuations in ore ratio, fuel / raw properties, and gusts, etc. Levels 21 and 22 of the charges per circumferential direction of the route may vary. That is, in the normal case, as shown in the right side, the mixed layers l2 and l3 in which iron ores are stacked in the order of weight are formed on the coke layer l1 on which cokesteras (T) is formed. If the charge level is different, the charging baseline becomes uneven by the circumferential direction, and if the deviation occurs more than a predetermined value (for example, 0.3 m), the charging trajectory is charged toward the furnace wall of the coke terrace due to the falling trajectory when charging the opposing sintered mine so that it is not settled at the tip end. Therefore, the mixed layer is not formed.

In the blast furnace operation, the gas does not flow into the ore layer having a small particle size and relatively little pores, and gas flows through the coke layer having a large particle diameter and relatively large pores. , The gas flow becomes uneven.

That is, as shown in Fig. 3A, the heat transfer is increased toward the lower charge level at which the coke terrace is formed shorter, so that the layer of the softening fusion zone 31 is not at the center and the charge level is not at the center. It moves down and changes the flow of gas in the furnace.

When the reaction between the gas and the charge becomes uneven in the furnace, the melting rate of the charge changes, and the shape of the soft fusion layer varies from direction to direction, and the amount of air entering the tuyere 9 changes, so that the charge level in the circumferential direction is not constant. The vicious cycle of uneven loading distribution of the route is repeated.

In addition, the lower load level of the lower charge level is faster, the lower portion of the lower softening fusion zone near the lower level 32 is enlarged and struck, so that the unreduced ore and the low temperature ore 33 directly falls Reduction is increased so that the temperature and chemical composition of the melt collected in the bottom part varies from outlet to outlet.

And, this, in turn, has a problem that causes a decrease in productivity and shortened life.

The present invention has been made to solve the problems described above, the purpose of which is to adjust the rotational speed of the turning shooter so that the charge level is charged in accordance with the upper level of the charge to the charge level is constant It is to provide a charging control method that is compensated for the level deviation of the blast furnace charge that can maintain and ensure the breathability of the soft fusion zone.

1 is a schematic diagram illustrating a process of charging fuel and raw materials into a general blast furnace.

Figure 2 is a schematic diagram showing the occurrence of laminar and deviation according to the change of the charging baseline when charging the fuel and raw materials into the blast furnace.

3 is a schematic diagram comparing the shape of the soft fusion zone when the level deviation occurs and when there is no level deviation.

Figure 4 is a graph showing the deviation compensation section for each circumferential direction in the blast furnace for explaining the rotational speed calculation process for compensating the deviation in accordance with the present invention.

5 is a flowchart illustrating a charging control flow to which a level deviation compensation method according to the present invention is applied.

Fig. 6 is a block diagram showing the configuration of a charging control device operating in accordance with the charging control method according to the present invention.

7 is a graph showing changes in the blast furnace internal temperature and the molten iron temperature in the case of the present invention compared with the prior art.

* Description of the symbols for the main parts of the drawings *

8: Turning Shooter

10: blast furnace

T: cokesteras

d: charging baseline deviation

41: charging baseline graph

As a constituent means for achieving the above object of the present invention, the present invention provides a charging control method in which the level deviation compensation of the blast furnace charge is made,

A first step of detecting the level of the load on the furnace wall along the circumferential direction when the charge to be charged into the blast furnace is imported and the charge reaches the charging baseline;

A second step of checking whether a deviation between the highest value and the lowest value of the charge level detected in the step is within a set management range;

If the charge level deviation is out of the management range, divide the furnace charging area into equal parts by a predetermined angle in the circumferential direction and divide it into a predetermined number of sections, and calculate a reference level by averaging the highest and lowest levels from the detected charge level, A third step of setting a section having a charge level lower than the reference level as a deviation compensation section, and calculating a volume in the furnace required until the average level returns from the deviation compensation section;

A fourth step of calculating the required amount from the volume calculated in the above step to returning to the average level based on the specific gravity and flow characteristics of each type of light and calculating the rotational speed of the swing chute according to the amount;

When the load level deviation is within the control range, the turning shooter is loaded at the set reference speed only.If the charge level deviation is out of the control range, the turning shooter is loaded when the deviation level is not within the deviation compensation section. A fifth step of charging while varying the swing speed is characterized in that the control.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail with reference to attached drawing.

Prior to describing the charging method according to the present invention, the concept of charging fuel and raw materials in the blast furnace will be described.

The reason why the length of coke terrace T should be constantly formed when charging lead / raw material in blast furnace 10 is that the length of coke terrace is formed in the total distance in the radial direction of the furnace to the area where no mixed layer l2 is formed. It is an area that does not change due to a factor, and since the small sintered ore l3 is charged as long as the coke terrace length T is formed, the area becomes a region where the flow of gas is relatively small, and the flow of the gas flow is small. The low temperature of the furnace wall portion ensures that the heat load of the furnace wall portion is stably managed, thereby achieving a desirable phenomenon of extending the blast furnace life. That is, in order to prolong the life of the nose, cokesteras must be formed to a certain length (for example, 1.0 m) to control the temperature of the furnace wall below a stable value.

In addition, when charging the sintered light while forming the coke terrace at the level of 1.0 m, as shown in the right side of FIG. 2, the mixed sintered light is charged so as to settle at the coke tip, thereby forming a mixed layer in the middle and the center to stabilize the gas flow. Although it is operating to induce, basically, it forms an ore and coke layer to induce gas flow through the coke layer, and then artificially creates a mixed layer in which a part of the coke layer and a part of the ore layer are mixed. It is to maximize the better breathable effect.

In the present invention, as described above, the upper level of the blast furnace charge is detected in the circumferential direction (360 degrees) so that a terrace of a predetermined length or more is formed to form a mixed layer, and the rotational speed of the turning shooter 8 to compensate for the level deviation. Calculate, which is

At this time, the upper level of the charge in the blast furnace 10, as shown in Figure 1, is detected by the level detector (7) provided on the blast furnace 10.

In the present invention, when the level of the furnace wall of the upper part of the blast furnace load detected by the level detector 7 along the circumferential direction appears as shown in the graph 41 shown in Fig. 4, in the present invention, the turning direction (circumferential direction) Therefore, it is divided into several sections by a certain angle. In the embodiment shown in FIG. 4, the charge level in the circumferential direction is divided into six sections at equal angles of 60 degrees.

In the graph 41, the highest level h1 and the lowest level h3 of the circumferential material blast furnace loading are detected, and the average level is obtained by taking the intermediate value between the highest level h1 and the lowest level h3. h2) is set, and the hatched portion whose charge level is equal to or less than the average level h2 is designated as the deviation compensation section 42, and the number of sections for which the deviation compensation is required is calculated. At this time, the deviation compensation section 42 includes all sections below the average level from the lowest level, and multiple selections are possible for each section, but considering the normal rotational speed of the turning chute 8 and the furnace section area of the blast furnace 10. In this embodiment, when divided into six sections, it is difficult to see more than three sections. If the deviation level (hatched portion) of the average level (h2) and the charge level is 50% or more of the corresponding section, this section is included in the deviation compensation section and excluded if it is less than 50%.

When the deviation compensation section is set in this way, the volume of the deviation compensation section is calculated as in Equation 1 below.

Then, as described above, the volume of the calculated deviation compensation section is multiplied by the specific gravity as shown in the following equation 2 and divided by the number of revolutions to calculate the amount of charge to be charged for the deviation compensation per revolution.

In the above, the specific gravity according to the mineral species of the charge is as shown in Table 1 below.

Optical species importance cokes 0.5 Sintered ore 2.0

Then, the rotational speed of the turning chute 8 for charging by the calculated charging amount is calculated. Normally, the swing chute 8 rotates at a constant speed (for example, 7.5 sec / 1 revolution, 60 Hz), and the turning speed should be lowered so as to charge more in the deviation compensation section where the charge level is lower than the average.

In the present embodiment, when the deviation compensation section is 1 section, 2 sections and 3 sections, the rotational speed and the amount of charge according to the type of light are calculated according to the above-described method, as shown in Tables 2 to 4 below.

Deviation compensation table when deviation compensation section is one section Frequency (Hz) Rotation speed (rpm) Time (sec / rotation) Total time (sec / rotation) Segment time (sec) Extra coke quantity (ton / 1 round) Extra ore amount (ton / 1 round) 60 1800 7.50 7.50 0 0 0 55 1650 8.18 7.61 0.11 0.0278 0.1636 50 1500 9.00 7.75 0.25 0.0611 0.3600 45 1350 10.00 7.92 0.42 0.1019 0.6000 40 1200 11.25 8.13 0.63 0.1528 0.9000 35 1050 12.86 8.39 0.89 0.2183 1.2857 30 900 15.00 8.75 1025 0.3056 1.8000 25 750 18.00 9.25 1075 0.4278 2.5200 20 600 22.50 10.00 2.50 0.6111 3.6000

Deviation compensation table when deviation compensation section is 2 sections Frequency (Hz) Rotation speed (rpm) Time (sec / times) Total time (sec / rotation) Segment time (sec) Extra coke quantity (ton / 1 round) Extra ore amount (ton / 1 round) 60 1800 7.50 7.50 0 0 0 55 1650 8.18 7.73 0.23 0.0556 0.3273 50 1500 9.00 8.00 0.50 0.1222 0.7000 45 1350 10.00 8.33 0.83 0.2037 1.2000 40 1200 11.25 8.75 1.25 0.3056 1.8000 35 1050 12.86 9.29 1.79 0.4365 2.5714 30 900 15.00 10.00 2.50 0.6111 3.6000 25 750 18.00 11.00 3.50 0.8556 5.0400 20 600 22.50 12.50 5.00 1.2222 7.2000

Deviation compensation table when deviation compensation section is 3 sections Frequency (Hz) Rotation speed (rpm) Time (sec / times) Total time (sec / rotation) Segment time (sec) Extra coke quantity (ton / 1 round) Extra ore amount (ton / 1 round) 60 1800 7.50 7.50 0 0 0 55 1650 8.18 7.84 0.34 0.0833 0.4909 50 1500 9.00 8.25 0.75 0.1833 1.0800 45 1350 10.00 8.750 1.25 0.3056 1.8000 40 1200 11.25 9.38 1.88 0.4583 2.7000 35 1050 12.86 10.18 2.68 0.6548 3.8571 30 900 15.00 11.25 3.75 0.9167 5.4000 25 750 18.00 12.75 5.25 1.2833 7.5600 20 600 22.50 15.00 7.50 1.8333 10.8000

However, Tables 2 to 4 are calculated by the coke 1 charge amount of 27.5 T, 1 rotation, allele charge 1 charge charge 108T, 10 rotations, the value is changed when the charge amount and rotational speed change.

As described above, a deviation compensation table for each number of deviation compensation sections is prepared, and the data is applied from the deviation compensation table created by comprehensively determining the charged ore type, ore amount, and deviation compensation section of the next charge to control the turning suit. do.

For example, if the next charged ore is coke, and the deviation compensation section calculated as described above is two sections, one rotation amount that can compensate the deviation level is automatically calculated and the deviation is applied by applying the coke amount of the nearest approximation calculated in Table 3. The rotational speed of the turning chute 8 for compensation is obtained.

Then, when the orbiting chute chute 8 rotates to charge ore and receives a signal that the deviation compensation section is reached from the stationary PLC (not shown) as the control system, the chute chute 8 is rotated at the speed selected in Table 3 above. Then, when the deviation PLC end signal is received from the top PLC again, the turning chute 8 is loaded while rotating at a constant speed again.

Here, when the difference between the highest level 620 and the lowest level 622 of the blast furnace load is more than a predetermined reference value (for example, 0.3m), the operator can be alerted so that the operator can know. In the above, the reference value is set to the level deviation at which the load distribution at the top of the blast furnace starts to be disturbed.

The charging control process of the blast furnace by applying the above method is explained with reference to the flowchart of FIG.

First, the ore, coke or iron ore to be charged through the conveyor belt (5) as shown in FIG. 1 is charged to the charging hopper (6), and charged to the target pressure for loading ore (502), the blast furnace 10 ) After charging a charge (coke or iron ore) to a predetermined reference line (503), the level detector (7) is lowered and the upper level of the charge in the blast furnace (10) is detected and read based on the circumferential direction, and the read level It is checked whether the deviation between the maximum level and the minimum level among the values is greater than or equal to the set value (504).

At this time, if the deviation between the maximum level and the minimum level of the charge is within the set range, there is no need to compensate, and after raising the level detector 7 as it is (505), without changing the rotational speed of the swing shooter 11, The charging is continued as it is (507).

On the contrary, if the difference between the maximum level and the minimum level of the charge in the comparison exceeds the set range, it is checked whether the deviation is compensated (506). When the deviation is not compensated, the level detector 7 is raised in the same manner as described above, and then charging is continued while the swing shooter 11 is rotated at the original constant revolution speed.

However, when the deviation compensation is set as described above, as described above, the portion below the average level is 50 on the basis of the average level obtained by averaging the maximum level and the minimum level among the divided sections of the furnace. A section of more than% is set as a deviation compensation section and the number is calculated (509).

Then, in the deviation compensation table as described in Tables 2 to 4 prepared as described above, the type of charges to be charged in the next charge and the number of deviation compensation intervals calculated in step 509 are different from the deviation compensation intervals for each type of charge. Read the amount of charge and rotation speed to compensate for the rotation (510).

Then, the read speed is applied to the swing shooter controller (i.e., the tripping PLC 605 of FIG. 6) so that the swing shooter 11 can be rotated at the set rotation speed (511), the swing shooter 11 Agitate.

Accordingly, the swing shooter controller rotates the swing shooter 11 at the initial set speed and accelerates the swing shooter 11 at the calculated speed when the deviation shooter reaches the deviation compensation section. In step 507, a larger amount of charge is made at the lower level.

7 is a comparison of the case of adjusting the rotational speed of the swinging shooter 11 according to the present invention and the conventional case, Figure 7a (A) shows the upper temperature of the radial charge when charging by the conventional method. (B) is a graph showing the upper temperature of the radial charge in the case of changing the rotational speed of the swing shooter 11 in accordance with the present invention, the temperature graph in the furnace is close to the left-right symmetry in accordance with the present invention It can be seen that.

In addition, FIG. 7B is a graph showing the upper temperature of the furnace contents according to the circumferential direction, where (A) is a conventional graph and (B) is a graph of the present invention. As shown, in the prior art, there is a difference in furnace temperature for each section, but in the case of the present invention, it can be seen that the furnace temperature difference for each section is almost disappeared.

In addition, Figure 7c is a graph showing the temperature deviation for each direction of the molten iron made in the furnace, as shown, the deviation occurred in the molten iron temperature, when adjusting the rotational speed of the swing shooter 11 in accordance with the present invention, It can be seen that the deviation almost disappears.

An embodiment of the apparatus to be charged control in the procedure according to the present invention is simply shown in block diagram as shown in FIG. Here, the input unit 601 is a means for inputting basic control data or indicating whether or not deviation is compensated and inputting the level value of the charge detected at the working place, and the process computer 602 is shown in Table 2 to Table 4 above. The deviation compensation table according to the number of deviation compensation sections calculated according to the present invention is stored, and as described above, the input level detection value of the charged item is input, and it is checked whether the deviation is within the set management range, and not within the set management point range. At this time, the deviation compensation interval is calculated by setting the deviation compensation interval in a section where the level lower than the reference level is 50% or more in each area based on the intermediate value between the highest loading level and the lowest loading level. Then, the correction revolution speed value is read from the deviation compensation table corresponding to the number of deviation compensation intervals.

Then, the sequential electric signal controller 603 according to the calculation result of the process computer 602

The tripping PLC 605 is a revolution speed control means, and converts the revolution speed into a control signal for directly controlling the revolution speed in accordance with a control signal input through the sequential electric signal controller 603.

In addition, the inverter 606 controls the power supply of the driving unit 607 that drives the swing shooter 8 according to the control signal from the stationary PLC 605 to vary the swing speed.

As described above, according to the present invention, the rotational shooter is not always rotated constantly, but the speed is adjusted so as to detect the level of the in-vehicle charge and charge more so that the lower amount is charged, so that the change of lead, raw material condition, charging equipment It is possible to keep the load distribution constant even if the level of the in-load charges in the circumferential direction is changed due to control problems, thereby improving the quality of the molten iron discharged from the blast furnace by maintaining the optimum air permeability at all times. Of course, the blast furnace has an excellent effect to promote productivity and life extension.

Claims (2)

In the charging control method in which the level deviation compensation of the blast furnace charge is made, A first step of detecting the level of the load on the furnace wall along the circumferential direction when the charge to be charged into the blast furnace is imported and the charge reaches the charging baseline; A second step of checking whether a deviation between the highest value and the lowest value of the charge level detected in the step is within a set management range; If the charge level deviation is out of the management range, divide the furnace charging area into equal parts by a predetermined angle in the circumferential direction and divide it into a predetermined number of sections, and calculate a reference level by averaging the highest and lowest levels from the detected charge level, A third step of setting a section having a charge level lower than the reference level as a deviation compensation section, and calculating a volume in the furnace required until the average level returns from the deviation compensation section; A fourth step of calculating the required amount from the volume calculated in the above step to returning to the average level based on the specific gravity and flow characteristics of each type of light and calculating the rotational speed of the swing chute according to the amount; When the load level deviation is within the management range, the turning shooter is loaded at the set reference speed only.If the charge level deviation is out of the management range, the calculated deviation compensation rotation speed is calculated in the deviation compensation section at the reference speed when it is not the deviation compensation section. A charging control method in which the level deviation compensation of the blast furnace charges is made by charging the furnace while varying the turning speed of the furnace. The charging control method of claim 1, wherein the level deviation compensation of the blast furnace load is performed by dividing the furnace charging area into six sections by dividing the furnace charging area by 60 degrees in the circumferential direction and then lowering the average level within the section by 50%. A charge control method in which a level deviation compensation of a blast furnace charge is set, wherein the section existing as an error is set as a deviation compensation section.