JPS5942734B2 - Control method of sintering operation - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for controlling sintering operations, and in particular, to a method for controlling sintering operations, which uses computer output based on a novel operation guide system to optimize ultimate control objectives such as productivity and product quality. This relates to a method of controlling operations.

Generally, it is well known that the ultimate control item in sintering operations is to produce sintered ore of stable quality in the required amount.

Regarding quality, strength, particle size distribution, chemical composition (Fe
It is important to satisfy target values such as O, CaO, 5t02, A40s), and it is also important that productivity is achieved with a high probability.

However, this alone is not enough; there are also other equipment management goals; for example, to prevent piping ducts from being damaged due to excessive negative pressure, it is necessary to keep the wind pressure inside the ducts within a certain range. In the same way, equipment management must be operated within certain standards, such as maintaining a constant exhaust air temperature to prevent condensation and ignition within the electrostatic precipitator, or to maintain the reaction efficiency of the desulfurization equipment. There is a need to continue to.

'Twofold, both of the management objectives mentioned above are achieved by maintaining the ventilation resistance of the sintered layer at an appropriate level.

However, due to changes in the composition and particle size of the raw material when cutting out the sintering raw material bed, particle size segregation of the raw material in the blending tank, changes in the permeability of the blended raw material layer due to changes in moisture content, and changes in the sintering completion position, The ventilation resistance of the sintered layer fluctuates greatly, which becomes a disturbance in maintaining stable operation.

Normally, an operator determines changes in operating target values over time and disturbances by observing various measurement results and instruments, and operates based on the operator's own experience based on the results.

However, there are more than 10 types of instruments to be monitored, and information such as measurement results is diverse.

Moreover, there are many operational factors such as cut, layer thickness, coke, damper opening, pallet speed, etc., and the operation that corresponds to the given information is the most appropriate one depending on the situation. must be selected and operated.

Due to these circumstances, the sintering operations currently underway are complex and rely on the operator's many years of experience and intuition.
The reality is that automation is limited to local control, so it is difficult to say that stable operations are being carried out.

Therefore, the present invention uses the air permeability level determination result, which is convenient for obtaining quantitative indexes for changes in operating conditions in sintering operations, to understand and judge, and to determine the most appropriate operation according to each situation. The purpose of this paper is to propose a control method for a sintering operation configured to be dynamically performed along the selective force axis.

The details of the configuration will be explained below.

This invention is a method in which a sintering operation is controlled by a computer using an operation guide system as described below based on a plurality of preset management items.

The operation guide system used in this invention basically consists of: (1) Comparison and judgment of target values of management items and actual values under operating conditions; (2) Air volume control and sintered layer control based on the judgment results of the first step. Determination of the air permeability level (3) Adjustment of ventilation level for equipment maintenance based on the judgment results of the first and second steps (4) Operation management based on the judgment results of the first and second steps.

This will be explained in detail based on the embodiment shown in FIG.

The process of (1) consists of judgment 1 for the target value of production volume, judgment 2 for the target value of sintered ore strength (example: shutter strength), and determination 2 for the target value of exhaust air temperature (example: exhaust gas temperature). It consists of the management items of Judgment 3 and Judgment 4 for the target value of exhaust air pressure (Example: Exhaust fan passing gas pressure).

Target values and allowable control ranges are set for each of these management items.

These target values and tolerance ranges are naturally determined by the sintering factory and surrounding conditions.

In this first step, the computer calculates the average value of the actual measured values of each control item at appropriate time intervals, and determines whether the average value is within an allowable range.

Then, if the average value is within the allowable range, O (zero),
+1 if it exceeds the allowable upper limit, - if it falls below the lower limit.
The configuration is configured to output a display of 1.

However, if the exhaust air pressure exceeds the upper limit, it corresponds to poor ventilation (-1), which will be described later, and only when the exhaust air pressure exceeds the upper limit, there is a problem in equipment maintenance.

Therefore, the exhaust air pressure will only exceed the upper limit (-1
) is output.

The judgment and air volume operation in the process of (2) are as follows: (1)
It operates based on the output content during the process.

If all the output contents in (1) are O (zero) 5; that is, if all the control standards are satisfied, the fluctuation 6 of the air flow rate passing through the sintered layer is determined in the computer according to formula (2).

1 (Q-cl)+ni'! −S1≧A・・・・・・・・・
・■i Here, Q: Air volume passing through the sintered layer, Wataru: Target air volume, K: Constant,
A: Air volume fluctuation tolerance range (Example 100 m/m1n).

■For the equation, if the left term is a dog than A, it is determined that the air volume fluctuates dog I.
The computer outputs a +1 or -1 display,
Based on the output, a cutting operation 8 is instructed to adjust the ventilation resistance of the raw material layer (an operation of changing the rotation speed of the drum feeder, adjusting the amount of raw material cut out, and adjusting the packing density of the sintered layer with the cut-off plate part). Ru.

In addition, if the left term of the formula (■) is smaller than A, it is determined that the air volume fluctuation is small, and the computer outputs an O (zero) display and no operation is performed. This is an average value, and the calculation and judgment of the equation (2) every 15 minutes are made by a computer.

In this way, the feature of this system is that the air flow rate passing through the sintered layer is used as an intermediate target to judge and control air permeability fluctuations based on quantitative criteria, and as a result, fluctuations in operational target values can be suppressed in advance. It becomes like this.

The air permeability of the sintered layer during this process can be observed using air resistance φ=P/Qn (where P: exhaust air pressure), but the goal of sintering operations is to accurately measure operational indicators such as production volume. Considering what we were trying to achieve, we decided that it would be appropriate to use an air volume that is theoretically proportional to the production volume.

Moreover, the target air volume Q adopted in this system was gradually changed using a moving average value in order to correspond to the operation targets of sintered ore strength, production volume, and exhaust air temperature.

The reason why the air volume Q is dynamically determined in this way is as follows.

That is, the measured values of the sintered ore strength and production amount are obtained 30 minutes after the sintered ore passes through the cooler after falling down the sintered strand.

Therefore, for example, if the standards for strength and production volume are satisfied, it is considered that the operational goals can be met in the future if the sintered layer air volume is maintained as it was about 30 minutes ago.

In the embodiment, the 5-point moving average value of the 15-minute average air volume was set as the target air volume, taking into account the 30-minute response time as described above.

The target air volume was calculated every 30 minutes.

Next, in the same process of <(3), if any one or more of the output contents in (1) is not 0 (zero), 11, that is, if any one or more of the management criteria is not satisfied, the following ■, (2) Determine the past and present air permeability level 10 using the formula.

・PRP is the past air permeability level.

P RP = TM/T O・・・・・・・・・ ■・
If the current breathability level is PRN, then Q PR = PRP 1α (- to Q-Q+)......■
t Here, TM: Exhaust air temperature, -T(,: Cooler exhaust air temperature, α, N: Constant.

The reason why the air permeability level of the sintered layer can be determined using formulas (1) and (2) is as follows.

When the ventilation resistance of the sintered layer increases while the pallet speed is constant, the sintering completion position moves closer to the ore discharge section, the exhaust air temperature decreases, and the cooler temperature increases.

When the ventilation resistance becomes smaller, the sintering completion position moves closer to the ore feeding section, and each temperature shows an opposite tendency.

That is, the level of ventilation resistance of the sintered layer can be estimated from the ratio of the exhaust air temperature to the cooler exhaust air temperature.

The reason why past values and current values are shown here is that there is a delay of about 30 minutes between the exhaust air temperature and cooler exhaust air temperature that are the basis of calculation, so the current air permeability level PRN is higher than PRP. Must be corrected for changes in air volume.

The reason why the past ventilation level PRP is used is that, as mentioned above, there is a delay of about 30 minutes in the sintered ore strength, production volume, and exhaust air temperature, so in order to accommodate these, the past ventilation level PRP is used. This is because calculation is required.

The level of breathability is determined based on a constant value (Example 0.7) for both past and current values, and +1 depending on the magnitude of the value.
(good ventilation) and -1 (poor ventilation) are determined.

For example, if one or more of the management standards are not satisfied, compare past and current ventilation levels and perform the following (3).
, In the process of (4), the air permeability level is modified in the desired direction.

This air permeability level is determined by the sintering completion position (B
TP) or by measuring the exhaust air temperature at the second wind box position from the end of the pallet, but the exhaust air temperature /
The cooler exhaust air temperature was found to be more reliable, so it was adopted.

The next step (3) is a step of directly adjusting the ventilation level mainly for equipment maintenance within the capacity range of each ventilation equipment.

The specific details of the operation are as follows.

(a) If it is determined that the wind pressure is high with a negative sign of 11, and it is determined to be 12 with the same sign as the current ventilation level (poor ventilation), the ventilation will be adjusted in the next process, but the wind pressure is high. When the ventilation is good, it is determined that the damper opening is excessive, and the damper opening is immediately reduced to 13 to directly adjust the ventilation.

(b) If it is determined that the exhaust air temperature exceeds the upper and lower limits (14) and has the same sign as the past air permeability level (15), the ventilation can be corrected in the next step.

However, if the exhaust air temperature appears with a sign of +1 or -1 and has a different sign from the past air permeability level, the amount of coke is adjusted to an appropriate amount 16.

(c) If the current air permeability level is judged to be different from the past air permeability level, and the exhaust air pressure is judged to be appropriate17, there is a possibility that the strength and production volume will be corrected naturally. However, if the ventilation levels are of the same sign (current and past) or the wind pressure is high, adjust the ventilation in the next step (4). It will be done.

Now, in the final step (4), in relation to the operational objectives given using the above-mentioned air permeability level as a control standard,
We will manage operations to satisfy these requirements.

(a) If the permeability is poor, the strength is low, and the production is insufficient (all codes are -1), 20, the firing is considered to be an inappropriate operation due to the firing being defective due to residual residue or lack of coke. , perform operation 21 of decreasing the pallet speed and increasing the coke.

(b) 22 when the breathability is good and 2 when the strength is low
3 is addressed by a cutting or layer thickness increasing operation 24.

On the other hand, if the strength is appropriate or excessive 23, operations 24 and 26 are performed depending on the excess or deficiency 25 of the production amount.

(c) In case of poor ventilation 22 and in case of excessive production 2
1, an operation 28 is performed to reduce the pallet speed.

On the other hand, if the production amount is appropriate or insufficient 27, the operation is divided into three operations 28, 31, and 32 depending on the intensity state 29 and 30.

The selection of operations in step (4) includes eight cases depending on the level of air permeability, strength, and production volume, and ensuring strength is prioritized over maintaining production volume.

The criteria for selecting these operations are based on the following relationships discovered through operational experience and operational data analysis.

(b) If the pallet speed is increased, the production volume will increase and the strength will decrease.

(r:J) When the layer thickness and cut are increased, the strength either remains the same or tends to increase, and the production volume remains the same or tends to decrease.

(c) When coke is added, the permeability decreases and the strength increases, and the production volume either remains the same or tends to decline.

Next, embodiments of the invention will be described.

A feature of the above-mentioned operation guide system of this embodiment is that the air flow rate passing through the sintered layer is set as an intermediate target during operation, and this air flow rate is different from that when operating based on the present invention. Table 1 shows a comparison of the fluctuations in the amount of air passing through the sintered layer when the operation was carried out according to the judgment of an experienced operator (normal operation).

As can be seen from this table, the air volume fluctuation (standard deviation of a fixed number of consecutive average values every 15 minutes) is smaller in the example of the present invention.

Furthermore, FIG. 2 compares the yield of sintered ore when operating using a computer and when operating normally based on the operation guide system of the present invention.

It can be seen that the method of the present invention has less variation in the quality of sintered ore and has an improved yield.

Note that the target values and allowable control ranges of each management item in the embodiment of the present invention are shown in Table 2.

As explained above, according to the present invention, changes in the strength and productivity of sintered ore, changes in equipment constraints, or changes in air permeability are judged based on quantitative criteria. Judgments based on intuition and experience are eliminated, and differences due to operational errors or operator experience are less likely to occur.

By setting and controlling the air volume and ventilation level as intermediate operational goals, we are able to prevent fluctuations in the final management goals.

Furthermore, since the operation is determined by comprehensively considering several different situations, the most appropriate operation depending on the situation can be selected.

Therefore, it has the effect of stabilizing the quality of sintered ore, improving the yield, and achieving the target production amount with high probability.

[Brief explanation of drawings]

FIG. 1 is a flowchart diagram illustrating automatic operation by the operation guide system according to the present invention;
FIG. 2 is a comparative transition diagram of the yield of sintered ore products, showing a comparison with a conventional example.

Claims (1)

[Claims] 1 The four items consisting of production volume, sintered ore strength, main exhaust air temperature, and exhaust air pressure are set in the computer as management standards, and the operation is automatically controlled based on the computer-included operation guide system. In this case,
The operation guide system consists of a first stage in which the target value of the management item is compared with the actual value under the operating conditions, an air volume operation based on the judgment result of the first stage, and a judgment on the permeability of the sintered layer based on the air volume. a second stage that adjusts ventilation levels for equipment maintenance based on the determination results of the first and second stages; and a third stage that adjusts ventilation levels for equipment maintenance based on the determination results of the first and second stages. A method for controlling a sintering operation, comprising: a fourth step of controlling the operation by level.