KR100423454B1 - Method for controlling the temperature of center portion of burden materials in blast furnace - Google Patents

Abstract

The present invention detects through the length of the coke terrace and the length of the center terrace of the charge and the thickness after the layer (thickness) that the unstable blast furnace operation is carried out by excessively lowered or excessively increased the center temperature of the surface of the blast furnace load. The present invention relates to a method for controlling the center temperature of the blast furnace hearth charge surface which is improved to stabilize the blast furnace operation by quickly recovering the center temperature of the blast furnace hearth charge surface through distribution control.

The present invention provides a method for controlling the central temperature of the blast furnace hearth charge surface in an optimum range, wherein the length of the coke terrace, the length of the center terrace of the charge, and its thickness (thickness) are detected to determine the surface of the blast furnace hearth charge. Detects excessively low or excessive rise in the center temperature and recovers the normal coke terrace length, the center terrace length of the charge and its thickness (thickness) through the distribution control of the charges in the next order, and thus the blast furnace roadbed The present invention provides a method of controlling the central temperature of the blast furnace hearth surface to maintain the blast furnace operation while maintaining the center temperature of the secondary charge surface.

Description

METHOD FOR CONTROLLING THE TEMPERATURE OF CENTER PORTION OF BURDEN MATERIALS IN BLAST FURNACE}

The present invention relates to a method for controlling the central temperature of the blast furnace hearth charge surface in an optimum range, and more particularly, the center temperature of the blast furnace hearth charge surface is excessively lowered or excessively raised, resulting in unstable blast furnace operation. Detecting through the length of the coke terrace, the length of the center terrace and the layer thickness (thickness) of the coke terrace, and through the control of the distribution of the charges to quickly restore the center temperature of the surface of the normal blast furnace load, so that the blast furnace operation can be stabilized An improved method for controlling the central temperature of the blast furnace hearth charge surface.

In general, the central temperature of the surface of the charge charged by the top charging device in the blast furnace operation has a large influence on the blast furnace blasting, but the control is not well controlled in the actual operation.

1 shows a blast furnace 50 to which the present invention is applied. The blast furnace 50 has a top hopper 55 is located on the upper side of the main body 52, a charge flow control valve 57 and the turning chute 60 is disposed on the bottom side of the top hopper 55, A charging reference line 62 is formed on the lower side of the turning chute 60, and a charge surface 65 is formed on the lower side of the charging reference line 62.

The softening fusion zone 67 and the melt 70 are formed on the lower side of the charge surface 65.

In the operation of the blast furnace 50, if the center temperature P of the charge surface 65 rises or falls, the length L1 of the coke terrace 100 and the center terrace 110 of the charge 8 and L2 The charge thickness t1 (t2) changes. This change can be measured by the charge shape measuring equipment 90 on the upper side of the charge. When the center temperature P of the charge surface rises, the change is charged by the top charging hopper 55 to soften the fusion splicer 67. The speed at which the charges 80 forming the drop descent in the vertical direction of the blast furnace 50 is slowed to increase the amount of heat input into the blast furnace 50 to increase the furnace temperature, increase the molten iron temperature, and increase the pressure according to the furnace direction. The fluctuations increase, resulting in worsening of the blast furnace 50 aging.

However, if the center temperature P of the surface of the charge is lowered, the charging speed at which the charge charged from the top hopper 55 descends in the vertical direction of the blast furnace 50 is increased, so that the amount of heat input into the furnace is reduced, and the furnace direction is lowered. There is no pressure fluctuation, but the molten iron temperature is lowered and the furnace temperature is lowered. As the lower part of the furnace body (Bosch and valleys) temperature is continuously lowered, deposits are formed at this part, and the blast furnace 50 is deteriorated.

On the other hand, when charging the ore and coke into the furnace when the charge surface center temperature (P) continuously maintains the trend of excessively falling, and then the shape of the charge using the charge shape measuring device 90 in FIG. As shown in the graph, in the normal operation, the length L1 of the coke terrace 100 and the length L2 of the central terrace 110 of the charge as shown in FIG. 5 are charged as shown in FIG. 6. It can be seen that the length of the center terrace 110 of the charge is longer than that when the water surface center temperature P is lowered.

And, the amount of the charge flowing into the blast furnace (50) is the distance between the ore and the center terrace (110) of the coke, that is, after measuring the layer (t20) than the layer after the normal operation state shown in Figure 3 (t2), It can be seen that the interval (after layer) t20 when the central temperature P of the charge surface central part 95 shown in FIG. 4 is lowered is thicker.

On the other hand, when the charge surface center temperature P of the furnace center part 95 falls, the in-vehicle breathability which shows the degree to which gas rises from the bottom of the blast furnace 50 improves, but it charges by the top charging hopper 55. The charge rate at which the charged charge drops in the furnace vertical direction is increased so that the furnace temperature measured by being installed in the furnace wall portion 92 gradually decreases, and the charge is attached to the furnace wall portion 92 so that the furnace 50 is radially in the blast furnace 50. As the diameter size decreases, the ventilation in the furnace begins to worsen.

If this condition persists, the blast furnace (50) gas flowing from the lower part to the upper part becomes uneven, and the gas charged into the vulnerable layer of the charged material temporarily flows, and the charged material by the top charging hopper 55 is disturbed. For long periods of time the blast furnace 50 deterioration deteriorates.

And, in contrast to the above, when the charge surface center temperature (P) continuously maintains the trend of excessively rising, the charges charged by the top charging hopper 55 is a charge of the blast furnace 50 vertically descending As the descent rate slows, the furnace temperature starts to rise, and the pressure in each direction installed in the blast furnace 50 body fluctuates. If this condition persists, the furnace temperature rises more and more, and the pressure fluctuations in each direction of the furnace also increase. In the case of the stave blast furnace 50, the temperature exceeds 197 ° C, which is set in terms of protection of the stave as a cooling facility. The equipment to be used by the end of the blast furnace (50) is damaged prematurely, so the equipment must be replaced at a high cost.

In addition, as shown in the phenomenon when the charge surface center temperature P decreases, the blast furnace 50 gas rising from the bottom of the blast furnace 50 becomes non-uniform, and a large amount of gas is instantaneously moved to a place where the charge layer is vulnerable. When raised, the charge layer is disturbed, resulting in a blast furnace 50 leading to a large operation accident 50.

Therefore, the inventors of the present invention, when the charge surface center temperature (p) excessively rises or drops sharply in the operation of the stave blast furnace 50 and the cooling panel type blast furnace 50, the charging by the top loading hopper (55). This study developed a charging method to closely examine the change in the shape of the charged charges so that the center temperature (P) of the charge surface becomes a steady state in a short time.

In addition, by applying this method to actual operation, it is possible to control the resulting lower temperature of the underbody, to control the fluctuations in the direction of the underbody, and to control the ventilation resistance index lower, thereby maintaining stability in the furnace.

The present invention has been made to solve the conventional problems as described above, the object is that when the blast furnace operation, when the center temperature of the upper charge surface charged by the top charging hopper excessively lowered, or suddenly rises, the charge charging method To control the central temperature of the surface of the charge, thereby preventing the formation of deposits on the furnace wall, and to provide an improved method of controlling the central temperature of the blast furnace hearth surface to improve the durability of the installation. Its purpose is.

1 is an enlarged configuration diagram showing the shape of the surface of the blast furnace load;

2 is an explanatory diagram showing a method for measuring the thickness of a charge in a blast furnace;

3 is a graph showing the shape of the charge at the center temperature of the charge surface in the normal operation of the blast furnace;

4 is a graph showing the shape of a charge when the charge surface center temperature of the blast furnace decreases;

5 is a graph showing the actual blast furnace charge surface shape during normal operation of the blast furnace;

6 is a graph showing the actual blast furnace charge shape when the charge surface center temperature of the blast furnace drops;

7 is a graph showing a method of controlling the charge surface center temperature when the shape of the blast furnace is changed;

8 is a flowchart showing the blast furnace operation according to the present invention step by step;

9 is a graph showing an example of actual operating performance when the charge surface center temperature of the blast furnace rises;

10 is a graph showing changes in the length of the coke terrace and the central terrace by adjusting the charge flow control valve when the surface temperature of the blast furnace is increased or decreased;

FIG. 11 is a graph showing changes after the charge layer by adjusting the charge flow control valve when the surface center temperature of the blast furnace is raised or lowered.

Explanation of symbols on the main parts of the drawings

50 ..... blast furnace 55 .....

60 ..... Turning Suit 80 .....

100 .... Coke Terrace 110 .... Central Terrace

L1, L10 ... coke terrace length

L2, L20 ... center terrace length

t1, t2, t10, t20 .... after layer

P ..... Center temperature

In order to achieve the above object, the present invention, in the method for controlling the central temperature of the blast furnace hearth surface in the optimum range, the length of the coke terrace and the length of the center terrace of the charge and its thickness (thickness) by detecting the blast furnace Detects excessively low or excessively elevated center temperature of the surface of the roadbed contents and controls the distribution of the charged contents in the following order, and the length of the normal coke terrace and the length of the center terrace of the contents and the thickness of the layer (thickness) It is to provide a method of controlling the center temperature of the blast furnace hearth charge surface to improve the blast furnace operation by maintaining the center temperature of the blast furnace hearth charge surface to recover to.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

In the method for controlling the center temperature of the blast furnace hearth surface according to the present invention, as shown in FIG. 8, charging is repeatedly performed by the charging sequence, and the center temperature P of the charge surface is controlled every 12 minutes. If it is within the scope of management and not within the scope of management, the steps of the present invention will be ignored and charged according to the routine charging sequence.

First, a step 210 of importing raw materials through the first and second hoppers 55 is performed, and a step 220 of closing and closing the upper valve 55a of the top hopper 55 is performed, and the blast furnace 50 Pressurizing 230 the hopper 55 so that the internal pressure and the pressure of the hopper 55 are matched.

Then, the rising step 240 of the device 58 for measuring the distance to the charges in the blast furnace 50 is made, the turning chute 60 is swiveled to charge the charges (250) is made In step 260, the turning chute 60 stops at the charging stand-by position and the charging of the charging is stopped, and the descending step of the device 58 for measuring the distance to the charging inside the blast furnace 50 ( 270 is made and a step 280 of completing the charging is made.

Then, a step 290 of determining the charge surface center temperature (P) is made, if the charge surface center temperature (P) does not deviate from the management range is linked to the sequential electrical signal controller 350 is a typical Charging takes place.

However, when the charge surface center temperature (P) is out of the management range, a step (300) of measuring the shape of the charge is performed by operating the charge shape measuring device (90), and in the step (300) After layer (t10) (t20), the length (L10) of the cokesteras 100, and the length (L20) of the coke center terrace 110 is measured, which is first measured measuring device 90 The furnace 50 measures the distance from the 700 mm point above the charging reference line 62 to the top of the charge as shown in FIG. 1 while passing through the top of the furnace charge.

Then, step 310 is performed to calculate these as numerical values. Next, check whether the length L10 of the coke terrace 100 and the length L20 of the coke center terrace 110 are within a management range, and when the range is within the management range, the electric signal controller 350 is connected to the sequential electric signal controller 350. The charging is carried out by the normal charging sequence, and when it is out of the control range, a step of adjusting the charge distribution is performed to maintain the charge surface center temperature (P) within the control range.

In the step of adjusting the charge distribution, calculation is made of how much the opening degree of the flow control valve 57 is to be adjusted in the next steps 330 and 340, so that the result is a sequential electric signal at the next charging. It is transmitted to the controller 350 to achieve the opening degree adjustment of the flow control valve 57, the charging of the charge is made.

This will be described in detail for each step as follows.

First, when the charge surface center temperature (P) in the step 290 is out of the management value, as shown in Figure 1, when the charge surface shape measuring equipment 90 is started to measure the shape of the charge, this Based on the measured data, in the next step 310, after the charge layer t10 (t20), i.e. thickness, is calculated, the formula is as follows.

T = H-[H _o + H ₁ ]

= H-(H _o + (H ₂ / TT)

= H-[H _o + (H ₂ / (Tch * BS))]

= H-[H _o + (H ₂ / (V _o / V ₁ * BS))]

Where T = charge thickness

H = the charge position after the last charge (N)

H _o = position of the N-1th charge

H ₁ = the position of the N-1th charged charge most recently over time

The load position at the moment the position of the measured charge is measured

H ₂ = distance from the tuyere to the charging reference line 62

Tch = the number of charging cycles into the volume from the tuyere to the charging baseline 62

TT = the time when the charge placed in the charging standard reaches the tuyere location

BS = time required to complete charging of one charge

V _o = volume from the tuyere to the charging baseline (62)

V ₁ = volume of one charge

After the charge layer thickness t10 (t20) is calculated by the above formula, the length L10 of the coke terrace 100 and the length L20 of the central terrace 110 are calculated.

To explain the calculation process, first, there are approximately 100 charge shape measuring points in the radial direction of the blast furnace 50, and 10 points are shown in FIG. The length L10 of the coke terrace 100 and the length L20 of the central terrace 110 are calculated by comparing the difference values of the positions of the respective charges.

As described above, when the charge surface center temperature P is out of the control value (for example, when the central temperature is excessively lowered), after the charge layer t10 (t20) and the coke terrace 100 The length L10 and the length L20 of the central terrace 110 are calculated, and the schematic of the result is shown in FIG. 4, respectively.

5 is a result of measuring the length of the charge (L1) (L2) and the layer thickness (t1) (t2) when the normal operation in the actual operation, Figure 6 is the temperature of the charge surface center temperature (P) is lowered It is the result of measuring the charge length (L10) (L20) and the layer thickness (t10) (t20) when it is out of control range. That is, FIG. 4 may be referred to as a simplified graph of the actual operating situation of FIG. 6, and FIG. 3 may be referred to as a simplified graph of the normal actual operating situation of FIG. 5, and these may correspond to each other.

Therefore, as shown in Figure 4, when the charge surface center temperature (P) is lowered out of the temperature control range, the length (L10) of the coke terrace 100 and the length (L20) of the central terrace 110 is normal operation. Among them, the length L1 of the coke terrace 100 and the length L2 of the central terrace 110 shown in FIG. 3 are markedly shorter than those measured.

In addition, when the length L10 of the coke terrace 100 and the length L20 of the central terrace 110 are short, the after-loading layers t10 and t20 of these portions are the after-layer shown in FIG. 3 during normal operation. It is thicker than (t1) (t2).

Accordingly, the length L1 of the coke terrace 100 and the length L2 of the central terrace 110 measured during the normal operation as shown in FIG. 3, and the charge layer thickness t1 (t2) of these portions. By comparing the measured values as shown in Figure 4 on the basis of the control value so that the charge position of the next charge and the number of charge rotation by position to control the charge surface center temperature (P) to be different 3, the length L1 of the coke terrace 100 and the length L2 of the central terrace 110 measured at the time of normal operation as shown in FIG. 3, and after the loading layer of these parts (t1) (t2). To match.

This is achieved through the charge flow control valve 57 and the turning chute 60. If the charge surface center temperature P falls outside the management range, the ore in the charge to be charged next time is The blast furnace 50 moves from the center portion 95 to the furnace wall portion 92, and the coke moves from the furnace wall portion 92 to the center portion 95. That is, the ore moves to the furnace wall portion 92 rather than the center of the blast furnace 50, and is charged in a biased manner, and the coke is charged into the furnace center portion 95 rather than the furnace wall 92.

However, if the charge surface center temperature P is high beyond the control range, the ore in the next charge to be charged moves from the furnace wall 92 to the center 95, and the coke is the furnace core ( 95 is charged by moving to the furnace wall portion 92. That is, the ore moves to the furnace center portion 95 rather than the blast furnace 50 furnace wall portion 92, and is charged unilaterally, and the coke is charged into the furnace wall portion 92 more than the furnace center portion 95.

Then, when the charge surface center temperature (P) is out of the management range and the rotational speed of the charge loading position and the rotational chute chute 60 for each position is changed, the charge flow control valve 57 is automatically adjusted to match this. The adjustment method is as follows.

Y = ax + b

Where Y is the charge flow rate and discharge rate = charge quantity / (speed * revolution chute speed)

a, b is a constant

x is the charge flow control valve 57 angle,

In the above equation, the angle of the charge flow control valve 57 is calculated.

Referring to the role of the charge flow control valve 57 in more detail, as shown in Figure 10, it shows the relationship between the coke terrace 100, coke center terrace 110 and the charge flow control valve 57 have. As can be seen in the graph of FIG. 10, when the charge flow control valve 57 is opened a lot, the charge discharge amount increases, and the length L1 of the coke terrace 100 and the length L2 of the central terrace 110 are shortened. do.

In the case of the coke terrace 100, when the charge flow control valve 57 is opened by 1 degree, the coke terrace 100 has a length L10 of about 8 to 10 cm shorter, and 1 degree close to the contrary.

In the case of the coke center terrace 110, the length L20 of the central terrace 110 is long when the charge flow control valve 57 is closed, and shortens when it is opened. That is, when the charge flow control valve 57 is closed by 1 degree, the length L20 is approximately 14 to 16 cm long, and when opened by 1 degree, the length is shortened by 14 to 16 cm.

In the case of the charge layer after (t10) (t20), as shown in Figure 11, closing the charge flow control valve 57 after the layer becomes smaller and thicker when opened. That is, when the charge flow regulating valve 57 is opened by 1 degree, the thickness t10 of the charge layer of the coke terrace 100 becomes about 10 cm thick, and when it is closed by 1 degree, the thickness becomes equally thin.

In addition, in the case of the charge layer layer t20 on the center terrace 110 side, when the charge flow control valve 57 is opened 1 degree, the thickness becomes about 6 to 7 cm, and when it is closed, the thickness becomes the same as the opposite .

9 is an example in which the present invention is applied when the charge surface center temperature (P) is excessively high in a practical operation. First, the results are described. The management temperature range is 350 to 6 to 7 hours after the start of the operation. It will come within 550 ℃. The action when opening and closing the flow regulating valve 57 is shown as shown in FIGS. 10 and 11.

After the opening degree of the flow regulating valve 57 is determined through the above-described process, the result is output to the monitor of the facility control computer (not shown), and the operator finally confirms by pressing the confirmation button through the monitor. And, after the confirmation is completed, the signal is transmitted to the sequential electric signal controller 350 so that charging is carried out so that the charge surface center temperature P is controlled, and after the charging is completed in step 280, the charge surface center temperature The process continues repeatedly until (P) is maintained within the control range (350-550 degreeC).

If the charge surface center temperature (P) is maintained within the control range (350 ~ 550 ℃), the result is known on the monitor output, and the operator confirms and presses the OK button to return to the charging mode in normal operation. Temperature control is terminated.

Therefore, in the present invention, as shown in FIG. 8, in order to prevent the charge surface center temperature P from being excessively low or high, the surface center temperature of the charge after the charge is completed in step 280 is controlled. Determination step 290 of the range is made, the charge surface shape is measured in step 300, and based on this data in the next step 310, the length of the coke center terrace 110 (L20), cokesteras ( The length L10 of the 100 and the charge layer thickness t10 (t20) are calculated, the length L20 of the coke center terrace 110, the length L10 of the coke steras 100, and the thickness t10. The data stored in the process computer is compared every time whether t20 is within the management range in the next step 320.

Then, if the control value is out of the control value (350 ~ 550 ° C) range is made to adjust the distribution of the charge in the next step 330 to be managed, in this step 330 determines the change value of the flow control valve 57 Then, the shape of the charge is measured and adjusted.

If this adjustment is repeated, the excessively degraded or elevated charge surface center temperature (P) is managed within the management temperature range (350 ~ 550 ℃) within a few hours to return to the normal operating level. That is, charging is continuously made in the state where the flow regulating valve 57 is adjusted, and when the loading surface center temperature P reaches the management range, the flow regulating valve 57 returns to the normal operation state.

Therefore, in the present invention, in order to reduce the work load of the operator in the blast furnace 50 operation, when the surface temperature of the charge is excessively lowered or rises, the measured shape of the charge is processed in the process computer to automatically process the coke terrace. The length (L10) and the after layer (t10) of the (100) and the length (L20) and the after layer (t20) of the coke center terrace 110, the length (L1) and after layer (t1) of the coke terrace 100 in a normal state and By adjusting the coke center terrace 11 to match the length L2 and the layer thickness t2, the center temperature of the furnace body P can be maintained at an appropriate level, and the furnace temperature of the blast furnace 50 can be managed at an appropriate management level. .

As described above, in the present invention, the length L10 of the coke terrace 100 having a charge shape when the charge surface center temperature P is excessively raised or lowered beyond the management standard value in the blast furnace 50 operation. , The length L20 of the center terrace 110, and the after-load layer (t10) (t20) of the normal management value, that is, the length (L1) of the coke terrace 100, the length (L2) of the center terrace (110) And, it is possible to detect whether it is out of the layer after loading (t1) (t2), and based on these data to adjust the flow regulating valve 57 of the top loading hopper 55, the position of the charge to be charged in the following order And charging by changing the rotational speed of each position, and finally has the effect of normally controlling the central temperature (P) of the surface of the charge.

In addition, when the load surface center temperature (P) is excessively reduced, as the production speed increases, the furnace body temperature decreases, and when the deposit is formed on the furnace wall, the air permeation resistance is worsened through the method of the present invention. ) Can be solved by the normal recovery, and there is an effect of preventing the formation of deposits on the furnace wall.

In addition, when the charge surface center temperature (P) is excessively increased, the furnace temperature is increased to excessively heat the equipment installed in the furnace body to shorten the life of the equipment through the method of the present invention. By recovering the temperature P normally, there is an effect that can be solved.

Claims (4)

In the method for controlling the central temperature of the blast furnace load surface in the optimum range, the length L10 of the coke terrace 100 and the length L2 of the central terrace 110 of the charge and its thickness (t1) (t1) (t2) to detect that the center temperature (P) of the blast furnace upper charge surface is excessively lowered or excessively raised, and the length of the normal coke terrace 100 is controlled through the distribution control of the charge charged in the next order. (L1) and the length (L2) of the center terrace (110) of the charge and the layer thickness (thickness) (t1) (t2) to recover the stabilization of the blast furnace operation while maintaining the center temperature of the normal roadbed charge surface Improved central temperature control of blast furnace hearth charges. 2. The method of claim 1, wherein maintaining the center temperature (P) of the surface of the normal hearth charge comprises: (280) the charge being completed; Determining whether the surface center temperature of the charge is in the control value range (290); A step 300 in which the charge surface shape is measured; Calculating the length L20 of the coke center terrace 110, the length L10 of the cokesteras 100, and the post-load layer t10 (t20) based on the data (310); The length L20 of the coke center terrace 110, the length L10 of the cokesteras 100, and the layers t10 and t20 are within the management range, and the data stored in the process computer is compared with each loading. 320; If the control value is out of the control step of adjusting the distribution of the charges to be managed within the management range (330); the central temperature control method of the blast furnace hearth surface. The method of claim 2, wherein the step 330 of adjusting the distribution of the charge is determined by determining a change value of the flow control valve 57, measuring the shape of the charge, and adjusting the flow control valve 57. In this state, charging is carried out continuously, and when the surface center temperature (P) of the charge reaches the management range, the flow regulating valve 57 returns to the normal operation state. Control method. The method of controlling the center temperature of the blast furnace hearth surface, characterized in that to prevent the formation of deposits on the furnace wall and to extend the life of the equipment by restoring the charge surface center temperature (P) normally. .