JP2725529B2 - Charge distribution control method in blast furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a charge distribution in a blast furnace which corrects a change in a load drop trajectory caused by wear of a bell of a bell type blast furnace and obtains a constant load drop trajectory.

[0002]

2. Description of the Related Art In the operation of a blast furnace, in order to stabilize the furnace condition, the state of the gas composition distribution and gas temperature distribution is grasped and the shape of the cohesive zone is controlled. Very important. That is, when there is more coke in the center of the furnace than in the furnace wall, the gas flow in the center becomes extremely strong, and the air permeability in the furnace is improved, but the blast furnace cross section cannot be used effectively, Not only does the productivity decrease, but the growth of the furnace wall inert zone is promoted and the unloading worsens. In severe cases, it falls and causes a tuyere bending damage accident.
On the other hand, if there is more coke in the furnace wall than in the center of the furnace, productivity is ensured, but the gas flow in the peripheral part becomes extremely strong, and the steel shell may become red hot, In some cases, a problem occurs in which molten iron drops on the tuyere.

[0003] Therefore, in the blast furnace operation, the gas distribution state in the furnace radial direction is grasped, and the ore or coke charging position in the furnace radial direction is adjusted so that the gas distribution state becomes appropriate. There is a need to. By adjusting the charging position of the charging material, it is possible to improve the blast furnace gas utilization rate and to operate at a low fuel ratio. As a method for adjusting the distribution of the charge in the bell-type blast furnace, there is a change in the stock line and a change in the charging sequence, but the function of adjusting the appropriate charge distribution is lacking. In addition, we install ore receiving goods called movable armor,
By adjusting the set position, a method of adjusting the charge distribution in the furnace and controlling the gas distribution in the furnace is adopted. However, in a bell-type blast furnace, it is difficult to uniformly charge the charged material in the furnace radial direction because the charged material is discharged at one time. Further, even when the ore is to be charged only on the furnace wall side, since the raw materials are all charged at the same position as described above, there is a disadvantage that the gas distribution cannot be finely adjusted.

[0004] As a method for solving the above-mentioned drawbacks, when controlling the gas distribution in the furnace of the bell-type blast furnace, a gas composition distribution or a gas temperature distribution in the furnace radial direction at the furnace top is used.
A method of controlling the gas distribution in the furnace by adjusting the bell opening or the bell opening speed and changing the falling trajectory of the charge in the furnace in the radial direction to adjust the distribution state of the charge in the furnace (particularly, No. 59-9109). However, with the prolonged operation of the blast furnace in recent years, the charging equipment, especially large bells and movable armor, which have a large effect on the charge distribution situation, may wear out, causing a change in the furnace interior charge distribution situation. .

[0005]

Conventionally, when a large bell and a movable armor of a bell type blast furnace are worn,
Movable armor can be corrected to some extent by the amount of extrusion, but in the case of a large bell, there is no means other than replacement and repair, and the repair man-hour and the amount of work are large.

SUMMARY OF THE INVENTION An object of the present invention is to correct the wear of a large bell and a movable armor of a bell-type blast furnace and to correct a change in the charge distribution due to the large bell wear to obtain a constant load drop trajectory. It is an object of the present invention to provide a method for controlling a charge distribution in a blast furnace.

[0007]

Means for Solving the Problems The present inventors have made various studies to achieve the above object. As a result, the wear amount of the large bell was measured at the time of a cold wind, etc., and the large bell opening degree and opening speed conditions that can obtain the same charge distribution as when the wear amount of the large bell was zero were simulated. It has been found that the change in the charge distribution caused by the above can be corrected by adjusting the opening degree or opening speed of the large bell, and reached the present invention.

That is, according to the present invention, the amount of wear of the large bell is measured in controlling the charge distribution of the bell type blast furnace, and based on the measured amount of wear, the same calculation as in the case of zero wear of the large bell is performed by a model calculation. The opening degree or opening speed of the large bell from which the load drop trajectory can be obtained is obtained by simulation, and the opening degree or opening speed of the large bell is controlled to the opening degree or opening speed obtained by simulation. The fluctuation of the load drop trajectory caused by the wear of the bell is corrected to obtain a constant load drop trajectory.

[0009]

[Function] In the operation of a bell-type blast furnace, when the load weight, large bell opening and opening speed are constant, the falling trajectory and initial velocity of the charge become constant, and simulation is performed by model calculation. can do. However, if the bell blast furnace is operated for a long period of time, the large bell and the like will wear, and even if operated under the same conditions, the fall trajectory of the charge and the initial speed will change, resulting in a change. The charge distribution fluctuates, making it difficult to maintain stable furnace conditions.

In the present invention, the amount of wear of the large bell or the like is measured at the time of a calm or the like, and the fluctuation of the charge distribution can be simulated by the above model calculation. Furthermore, it is possible to simulate large bell opening and opening speed conditions that can obtain the same charge distribution as when the amount of wear of a large bell or the like is zero. Variations in object distribution can be corrected without replacing large bells.

[0011]

【Example】

Embodiment 1 The details of the method of the present invention will be described below with reference to FIG. 4 showing an embodiment. FIG. 4 is a schematic explanatory view showing a large bell control system of a bell blast furnace used for carrying out the method of the present invention. FIG.
1 is a bell rod for suspending the large bell 2, 3a
Denotes a charge to be charged, and 5 denotes a bell hopper. The upper end of the bell rod 1 is connected to one end of a bell lever 7 having a counterweight 8 at the other end. By operating a hydraulic cylinder 9, the bell lever 7 is tilted about a fulcrum 10, and the large bell 2 is opened and closed. ing.

Reference numeral 11 denotes a large bell opening detector provided on the bell lever 7 of the drive system of the large bell 2. The same charging when the wear amount is simulated by a model calculation based on the wear amount measurement result of the large bell 2 is the same. It is used for adjusting the opening of the large bell 2 to obtain the object distribution. Reference numeral 12 denotes a flow control valve provided in the hydraulic pipe 13 of the hydraulic cylinder 9, which is capable of obtaining the same charge distribution as in the case of zero wear amount simulated by model calculation based on the wear amount measurement result of the large bell 2. It is used for adjusting the opening speed of the large bell 2 as the opening speed of the bell 2.

Since the large bell 2 is worn due to continuous operation for a long period of time, the fall trajectory and the initial velocity of the charge 3a are changed even at the same set opening degree, and the charge distribution is changed. If it fluctuates, the amount of wear of the large bell 2 is measured at the time of the calm, and the distribution of the charged material (O / C) in the furnace in the radial direction is simulated by the model calculation. The large bell opening or the opening speed that can obtain the same charge distribution (O / C) as in the case of is simulated, and the opening or the opening of the large bell 2 is set to a simulated value. The set opening speed is changed, the opening of the large bell 2 is adjusted by the large bell opening detector 11, and the opening speed of the large bell 2 is adjusted by the flow control valve 12 of the hydraulic pipe 13, and the charging in the furnace radial direction is performed. Correct the distribution of the material so that it is the same as when the wear amount of the large bell is zero. .

Embodiment 2 FIGS. 1 to 3 show coke in the case where the movable armor is used when charging coke and the movable armor is not used when charging ore and the opening is adjusted in accordance with the wear of the large bell. FIG. 4 is an explanatory diagram showing a relationship between a falling trajectory and a ratio of ore O and coke C in a furnace radial direction, that is, O / C.
FIG. 1 (a) shows a case where the wear amount of the large bell is zero, and shows a falling trajectory 4 of the coke 3 in a state where the large bell 2 is opened at a set opening by operating the bell rod 1. FIG. In addition, 5
Indicates a bell hopper and 6 indicates a movable armor. FIG. 1B shows the O / C in the radial direction in the furnace in this case. FIG. 2A shows that when the large bell 2 has been worn for a long period of use by the wear amount A and the large bell 2 has been opened to the set opening by operating the bell rod 1, a part of the coke 3 is moved to the movable armor 6. The falling locus 4a when falling to the furnace wall side without hitting is shown. The O / C in the furnace radial direction in this case is shown in FIG. FIG. 3A shows a falling trajectory 4b of the coke 3 when the opening adjustment amount B corresponding to the wear amount A of the large bell 2 shown in FIG. 2A is adjusted. FIG. 3B shows the O / C in the radial direction in the furnace in this case.

As shown in FIGS. 2A and 2B, when the large bell 2 is worn, a part of the coke 3 falls to the furnace wall without hitting the movable armor 6,
The charge distribution (O / C) in the furnace radial direction is lower on the furnace wall side and the gas flow on the furnace wall side is increased as compared with the case where the wear amount of the large bell 2 shown in FIG. 1 (b) is zero. , Furnace conditions fluctuate. Therefore, the wear amount A of the large bell 2 was measured, and the large bell 2 opening degree at which the same charge distribution (O / C) as obtained when the wear amount of the large bell 2 was zero was simulated. When the opening adjustment amount B was obtained and the opening was adjusted as shown in FIG.
As shown in FIG. 3 (b), the charge distribution (O / C) in the furnace radial direction can be modified in the same manner as in the case of zero wear of the large bell 2 shown in FIG. 1 (b). Was.

[0016]

As described above, according to the method of the present invention, only by installing an opening detector in the large bell control system and the flow control valve in the hydraulic piping of the hydraulic cylinder, the radial direction in the blast furnace due to the large bell wear can be obtained. The fluctuation of the charge distribution can be corrected, the furnace condition can be maintained stably, and the service life of the large bell can be extended. Can be reduced.

[Brief description of the drawings]

FIG. 1 shows the locus of coke falling and the distribution O / C of charged material in the furnace radial direction when the wear amount of a large bell is zero.
(A) is an explanatory view of a locus of coke falling when the large bell is opened at a set opening, and (b) is a graph showing the relationship between the radial direction in the furnace and the charge distribution O / C in this case. It is.

FIG. 2 shows a locus of coke falling and a distribution of charged material O / C in a radial direction in the furnace when the wear amount of the large bell is A.
(A) is an explanatory view of a locus of coke falling when the large bell is opened at a set opening, and (b) is a graph showing the relationship between the radial direction in the furnace and the charge distribution O / C in this case. It is.

FIG. 3 shows a locus of coke falling when the large bell opening adjustment amount B is changed corresponding to the large bell wear amount A so that the same coke falling locus as when the wear amount of the large bell is zero is obtained. FIG. 4A shows the distribution of charged materials O / C in the radial direction. FIG. 4A is an explanatory view of a locus of coke falling when the opening is opened with a large bell changed, and FIG. It is a graph which shows the relationship between a radial direction and charge distribution O / C.

FIG. 4 is a schematic explanatory view showing a large bell control system of a bell blast furnace used for carrying out the method of the present invention.

[Explanation of symbols]

 Reference Signs List 1 bell rod 2 large bell 3 coke 3a charge 4,4a, 4b falling locus 5 bell hopper 6 movable armor 7 bell lever 8 counter weight 9 hydraulic cylinder 10 fulcrum 11 opening detector 12 flow control valve 13 hydraulic piping A large bell wear Amount B Large bell opening adjustment amount

Claims (1)

(57) [Claims] 1. A method for controlling the charge distribution of a bell-type blast furnace, wherein the wear amount of a large bell is measured, and the same charge as in the case of zero wear amount of the large bell is calculated by a model calculation based on the measured wear amount. The opening or the opening speed of the large bell from which the falling trajectory is obtained is obtained by simulation, and the opening or opening speed of the large bell is controlled to the opening or opening speed obtained by the simulation. A method of controlling the distribution of charges in a blast furnace, wherein a variation in the load drop trajectory caused by the above is corrected to obtain a constant load drop trajectory.