JPH039163B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for charging contents into a blast furnace,
In particular, a
Alternatively, the present invention relates to an improvement in a method for charging contents into a blast furnace equipped with two or more bells.

[Conventional technology]

Generally, the charging and distribution control of raw materials into the blast furnace is
It varies depending on the raw material properties and the amount of raw material charged. Therefore, in order to maintain appropriate and stable gas distribution and temperature distribution in the furnace, for example, if the gas flow is strong at the center of the furnace, it is necessary to charge ore toward the center of the furnace or to place coke in the furnace. It is necessary to suppress the excessive gas flow in the center by charging the gas toward the wall side. Conventionally, this control involves adjusting the so-called movable armor notch position and the stock line level. If the layer thickness of coke or ore in the radial direction inside the furnace is appropriately controlled through this adjustment, it becomes possible to improve the blast furnace gas utilization rate and operate at a low fuel ratio. However, when controlling the burden distribution in a bell-type blast furnace, it is difficult to finely control the appropriate burden distribution by adjusting only the position of the movable armor notch and the level of the stock line, which are limited distribution adjustment elements. It was pointed out that it cannot be adjusted. In other words, in a bell-type blast furnace, the charged material is discharged all at once from the bell, so it is difficult to charge the ore evenly in the radial direction of the furnace. This method had the disadvantage that the gas distribution could not be finely adjusted because all the raw materials were fed into the same position. As a technology to eliminate this drawback, JP-A-59-
Some of these are disclosed in Publications No. 9108, No. 59-9109, and No. 59-41403. This method is based on the bell opening,
Or by adjusting the bell opening speed,
By controlling the charging amount and charging position of raw materials, we have solved the disadvantage of bells that they are charged at the same position at the same time.
This is intended to optimize the distribution of the charge in the radial direction within the furnace, that is, the gas distribution. The difference between this method and the previous method will be explained with reference to FIG. FIG. 3 shows a motion diagram of the large bell, with the horizontal axis representing time T (sec) and the vertical axis representing the opening degree P (mm) of the large bell. The driving source for the large bell is a hydraulic cylinder, and the opening and closing of the large bell is controlled by the opening and closing operation of a solenoid valve in this hydraulic circuit. In the previous method, the solenoid valve of this hydraulic circuit was simply fully opened or fully closed, so the third
As shown in the solid line graph in the figure, the large bell moves at full speed (fastest speed) all at once to the large bell fully open position P ₀ . This position P ₀ is, for example, 630 mm, and the time T required for this is set to, for example, 10 seconds. Therefore,
This has the disadvantage that the raw materials fall in the same place all at once. On the other hand, according to the improved conventional control method, the third
As shown in the dotted line graph in the figure, the large bell is not opened to its fully open position P ₀ , but the opening degree is stopped midway through, and the opening operation time (speed) is adjusted so that the raw material is slowly fed into the large bell. It is made to fall depending on the opening degree. The final bell opening time and degree of opening (Ti, Pi) in this method are varied for each type of raw material or batch as shown by the various dotted lines in Figure 3.
It is set to have the optimum distribution of raw materials in the furnace.
In this case, each final bell opening time and opening degree are:
The relationship is set to be almost inversely proportional. This is because if the bell opening time is short, it is necessary to ensure that the opening is sufficient for the raw material to fall.
Conversely, when the bell opening degree is small, it is necessary to ensure a sufficient opening time to discharge the entire amount of raw material from the large bell within the range of the small opening degree. When adjusting the operating speed of the large bell in this improved conventional control method, the opening degree of the solenoid valve in the aforementioned hydraulic circuit is narrowed down, that is, by adjusting the opening position of the solenoid valve, the pressure applied to the hydraulic cylinder is adjusted. This is done by adjusting the amount of oil. The qualitative tendency of this control method is that when the bell opening degree is made smaller or the bell opening speed is made slower, more raw material accumulates on the furnace core side. When the bell opening degree is increased or the bell opening speed is increased, a large amount of raw material accumulates on the furnace wall side. can be mentioned. Therefore, it is attracting attention as an effective method for adjusting the gas distribution in the blast furnace at present.

[Problems to be solved by the invention]

However, when this control method is actually applied, the following problems are pointed out in terms of control. A. Even if the hydraulic solenoid valve is set to the corresponding opening degree to obtain the specified opening speed (for example, Pi/Ti in Figure 3), changes in the temperature, viscosity, turbidity, etc. of the oil in the hydraulic circuit, Or the properties of the raw materials on the large bell (particle size, weight, type, blending ratio)
The actual large bell speed is not always constant due to changes in weight due to the discharge of raw materials from above the bell, and as shown in the two-dot chain line in Figure 3, the actual speed of the large bell is (Ti′, Pi)
(Ti, Pi′)
As a result, a slight fluctuation occurs, making it impossible to strictly control the in-furnace loading and distribution. B. The opening time and opening degree (Ti, Pi) mentioned above are subject to frequent setting changes, and the operating time is short (MAX 40 seconds), so they must be controlled instantaneously. Therefore, a relatively large-scale computer is required, leading to an increase in cost.

[Purpose of the invention]

The present invention has been made in order to solve the above problems, and the temperature of the oil in the hydraulic circuit,
Regardless of changes in viscosity, turbidity, etc., changes in the properties of the raw material on the large bell, or changes in weight as the raw material is discharged from the bell, the bell will open at the intended opening at the intended time. As a result, the distribution of the charge in the radial direction inside the furnace can be adjusted freely and accurately, and the adjustment does not require extensive calculations and requires frequent It is an object of the present invention to provide a method for controlling charge injection into a blast furnace that can sufficiently cope with setting changes or short-time control.

[Means to solve the problem]

The present invention provides a bell equipped at the top of a blast furnace.
In a blast furnace charging method in which the charge is charged into the furnace while adjusting the opening speed of the bell located at the lowest stage, the opening speed is calculated from the previously set opening speed and the actual opening speed. It includes a procedure for determining the deviation, a procedure for calculating a corrected opening speed based on this opening speed deviation, and a procedure for correcting the set opening speed by this corrected opening speed and then setting this as the next set opening speed. In this way, the above objectives have been achieved.

[Effect]

As mentioned above, there are many uncertain factors that affect the opening speed of the large bell, such as changes in the properties of the oil, changes in the properties of the raw material on the large bell, and changes in weight as the raw material is discharged from the top of the bell. , and they interfere with each other. The reality is that it is extremely difficult to quantitatively understand each of these individually, and there is no effective means to do so. Even if it were possible to grasp each individual element quantitatively, reflecting all of them in the control would require an extremely complex program, which would require frequent setting changes and short operating times. In this case, it is almost impossible to achieve this goal. Therefore, in the present invention, we focus on the fact that these elements are relatively constant over a short time period (for example, the oil temperature at the time of current charging is not much different from the oil temperature at the time of previous charging). However, based on the past speed deviation results, we have grasped the elements of these changes and have been able to sequentially reflect these changes in the latest bell operations for control, allowing highly accurate opening control regardless of these changing elements. As a result, the intended distribution of the charge can be achieved.

【Example】

Embodiments of the present invention will be described in detail below based on the drawings. FIG. 2 schematically shows a cross section of the vicinity of the top of a blast furnace to which the method for charging contents into a furnace according to the present invention is applied. First, to explain this device, the large bell 2 located below the small bell 1 is balanced by a counterweight 5 via a bell rod 3 and a segment 4, and is driven by a hydraulic cylinder 6. Ru. This hydraulic cylinder 6 is driven up and down by pressure oil from a hydraulic unit 7 via a solenoid valve 8, and this is linked to the opening and closing movement of the large bell 2. On the other hand, the raw material is transferred to the small bell 1 by the rotating chute 9.
Temporarily deposited on top, then 2 small bells 1 and 2 large bells
While equalizing and discharging pressure is adjusted by two bells, two large bells
deposited on top. Thereafter, the large bell 2 collides with the movable armor 10 or the armor plate 10A by the opening operation, and the fall position in the radial direction is adjusted and the raw materials are stacked on the stock line A. Now, in the previous raw material charging method, the large bell 2 was simply controlled to open at full speed to the fully open position by switching control of the solenoid valve 8, and return to the fully closed position again after the fully open position was detected. In this embodiment, the large bell 2 is driven according to the specified opening time TSi and the opening speed VSi based on the opening degree PSi, so the falling position and amount of the raw material on the stock line A in the radial direction inside the furnace can be controlled. Fine adjustment is possible. Specifically, this opening speed control is achieved by connecting a servo motor 1 to the oil line 15 which becomes the return side piping during the opening operation of the large bell.
A flow control valve 11 whose opening degree is adjusted at 6 is provided to control the flow rate of oil in this oil line 15. In this embodiment, in order to give an appropriate opening command to the flow control valve 11, a furnace sequence control device 12 is installed which has an arithmetic memory function for correcting the opening speed of the large bell 2. has been done. This furnace sequencer 12 receives the output signal of a pulse transmitter 13 provided on the rotating shaft 17 of the segment 4 and the desired large bell in order to capture each movement of the large bell 2 during the opening operation. It is configured to receive an output signal from a large bell opening time/opening degree setting input panel 14 for setting the opening time TSi and opening degree PSi of No. 2. Next, the operation of the calculation and storage function of the opening speed correction control of the large bell 2 of this embodiment will be explained in detail. First, as shown in FIG. 3, the large bell opening time and opening degree (TSi, PSi) for an arbitrary number of batches are arbitrarily set and input using the large bell opening time/opening degree setting input panel 14. All of the values (TSi, PSi) are taken into the furnace top sequence control device 12 and stored. These stored values (TSi, PSi) are sequentially retrieved as the batch progresses in the furnace top sequence and are calculated and converted into the large bell speed set value VSi=PSi/TSi. On the other hand, apart from this, the furnace top sequence control device 12 calculates the corrected opening speed △Vi by calculating the following equation (1) in accordance with the batch progress of the furnace top sequence.
This is executed step by step. △Vi=K△V _i-1 + (1-k)△ _i-2 ...(1) Here, △V _i-1 is the previous (i-1) large bell speed setting value VS _i-1 and the actual result value V _i-1 of the control based on it. Note that this actual result value V _i-1 is a combination of the actual final large bell opening P _i-1 based on the pulse count value of the pulse generator 13 and the timer count value T _i-1 that reached that position. Result (P _i-1 /
T _i-1 ). △ _i-2 is the large bell speed setting value VS _i-2 up to the previous time (i-2) and the actual result value of control based on it
This is the calculation result of the moving average value with the difference value from V _i-2 . k is a constant that adjusts the weight balance of either the previous performance difference value ΔV _i-1 or the previous performance moving average difference value Δi _-2 . In this embodiment, k is set to a value close to 1 in order to preferentially reflect the previous performance ΔV _i-1 in the next control as much as possible. Note that when k=1, the correction is based only on the previous performance. Next, using the calculation result △Vi based on the above,
Correct the large bell speed setting value VSi mentioned above. That is,
The value of [VSi+ΔVi] is given to the flow control valve 11 as the control setting value for this time (i). In the flow control valve 11, the opening degree of the oil line 15 to the electromagnetic valve 8 is adjusted by the servo motor 16 as position control proportional to the control setting value. The large bell 2 operates in accordance with the control setting value [VSi+ΔVi], and finally stops at the set open position PSi under the computation of comparison with the pulse signal of the pulse transmitter 13. Here, the reason why the stop is not limited by the set opening time TSi is to prevent the operation speed from being abnormally fast and stopping before reaching the set opening position PSi, resulting in insufficient discharge of the raw material. . In this embodiment, the above introduction method is used to perform optimal control while correcting subtle process changes over time.

【Effect of the invention】

As explained above, according to the present invention, changes in the process that have a high degree of change over time, such as changes in properties such as oil temperature, viscosity, and turbidity, and particle size, weight, and type of raw materials on the large bell , changes in properties such as blending ratio,
Alternatively, it is now possible to control the opening degree and opening speed of the large bell with high precision, regardless of changes in weight due to the discharge of raw materials from above the bell.
As a result, an excellent effect can be obtained in that the charge can be introduced in a desired distribution state in the radial direction within the furnace. In addition, since the control is relatively simple, it can be executed by a simple computer, and can sufficiently cope with frequent setting changes or short-time control.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the gist of the method for charging materials into a blast furnace according to the present invention, FIG. 2 is a skeleton diagram of the vicinity of the top of a blast furnace to which an embodiment of the present invention is applied, and FIG. , is a diagram showing the relationship between the opening time and opening degree of the large bell. 1... Small bell, 2... Large bell, 6... Hydraulic cylinder, 7... Hydraulic unit, 8... Solenoid valve, 10
... Movable armor, 11 ... Flow control valve, 12 ... Furnace top sequence control device, 13
...Pulse transmitter, 14...Large bell opening time/opening degree setting input panel.

Claims (1)

[Scope of Claims] 1. Charge into the furnace of a blast furnace, in which the charge is charged into the furnace while adjusting the opening speed of the bell located at the lowest stage among the bells provided at the top of the blast furnace. In the method, there are two steps: calculating the opening speed deviation from the previously set opening speed and the actual opening speed, calculating the corrected opening speed based on this opening speed deviation, and increasing the set opening speed by this corrected opening speed. A method for charging materials into a blast furnace, comprising: a step of correcting the opening speed and then setting it as the next set opening speed;