JPH0587464A - Controlling method for sintering completion point in sintering machine - Google Patents

Abstract

PURPOSE:To make proper the estimated values and make small the scatter in them by comparing the sinter completion point that is estimated from the discharged air temperature and an actual sinter completion point and regarding the estimated sinter completion point as abnormal and replacing it with an estimation value that is calculated based on actual sinter completion points up to present if the difference between those estimated and actual sinter completion points is larger than a specified value. CONSTITUTION:A raw material 2 is supplied to a pallet 3 from a supply ore hopper 1, and by operating a main blast discharge machine 7 while the pallet 3 is moving toward an ore discharge by a drive mechanism 4 air is sucked from an upper wind box to a lower wind box 5 and the calcination section 15 is moved from the upper section to the lower section in the state that ignition is made by an ignition furnace 9. In this movement the temperature of each discharged air is measured by a thermometer 8 that is provided at each wind box, and from the results of those measurements a sintering completion point is estimated by a sintering point controller 13 and the pallet speed is controlled. And an estimated sintering completion point is compared with the actual sintering completion point, and if the difference is larger than a specified value, the estimated sintering completion is regarded as abnormal, and it is replaced by an estimated value calculated based on actual sintering completion points in the past so that the estimated value becomes proper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a sintering completion point of a raw material in a DL type sintering machine to a target position by adjusting a speed of a pallet for transporting the raw material.

[0002]

2. Description of the Related Art Control of a sintering completion point in a conventional sintering operation is important for stabilizing the sintering operation. The sintering completion point is a guideline that indicates the position where the raw material on the pallet in the sintering machine is ignited on the surface in the ignition furnace and the calcination progresses downward from the surface as the pallet progresses to complete the calcination. It is closely related to the quality and productivity of the sintered sinter. When this sintering completion point changes from the target value to the ore feeding side, the quality of the sintered ore improves, but the quality specifications become excessive, the manufacturing cost increases, and the productivity of sintering decreases. On the other hand, if the sintering completion point fluctuates toward the slag ore side, the quality of the sintered ore deteriorates, which causes unburned residue and reduces the yield.

Conventionally, as a method for controlling the sintering completion point, the rising point of the exhaust temperature is detected from the exhaust temperature distribution in the conveying direction of the sintering machine by the exhaust temperature measuring device provided in each air box, The sintering completion point is predicted from the exhaust air temperature at the rising point, the sintering completion point is predicted from the raw material air permeability before ignition, and the pallet speed is sequentially corrected so that the sintering is completed at the target position. The control was performed so that the sintering was completed at the target position.

[0004]

However, although the prediction accuracy of the sintering completion point at the rising point of the exhaust air temperature is high, the rising point and the sintering completion point are close to each other, so that it is possible to deal with a large disturbance. In order to finish the sintering completion point at the target position, the variation prediction point of the sintering completion point is too late to be supported.

Further, the control of the pallet speed based on the predicted value of the sintering completion point based on the air permeability before ignition can cope with a large fluctuation of the sintering completion point at an early stage, but the prediction accuracy is slightly poor. There is. Further, the estimation error of the predicted value is not always constant, and a large error may occur depending on the operating conditions. At this time, conventionally, a method such as setting a limit value above and below the predicted value to prevent a large variation has been taken, but the variation direction of the sintering completion point is reversed, that is, the actual value of the sintering completion point is When it is larger than the target value and smaller than the target value, the control may disturb the sintering operation.

Further, since the control is performed by focusing only on the sintering completion point, there is a problem that unburned residue (sintering failure) increases when the pallet speed is increased when the heat level of the sintering bed is low. .. The present invention has been made by paying attention to the above problems, and an object thereof is to control so that the variation of the actual sintering completion point with respect to the target position becomes small.

[0007]

In order to achieve the above object, a sintering completion point control method in a sintering machine according to the present invention comprises:
In the sintering completion point control method that controls the pallet speed based on the sintering completion point predicted from the exhaust air temperature measured in each air box in the downward suction sintering method to bring the sintering completion point close to the target position If the deviation of the actual sintering completion point from the target position is outside the specified range, the pallet speed is corrected based on the deviation, and if the deviation is within the specified range and the wind box in front of the ignition furnace The measured air permeability of the raw material is worse than the specified value,
When the sintering completion point predicted from the air permeability is on the mine ore side than the sintering completion point predicted from the exhaust gas temperature, the target position of the sintering completion point predicted from the air permeability. It is characterized in that the pallet speed is corrected based on the deviation from.

At this time, when the deviation of the sintering completion point predicted from the exhaust gas temperature with respect to the actual sintering completion point is within a predetermined range, the sintering completion point predicted from the exhaust gas temperature is calculated in advance. It is advisable to replace it with the value estimated from the actual sintering completion point of, or the transition tendency of the actual sintering completion point to date. Further, when the temperature of the exhaust air passing through the air box at the sintering completion point is equal to or lower than the predetermined lower limit value, the acceleration of the pallet may be stopped.

[0009]

When the deviation of the recent actual sintering completion point from the target position is out of the predetermined range, there is a rapid process fluctuation, and the pallet speed is corrected based on the deviation to cope with the fluctuation. Then, the actual sintering completion point is brought closer to the target point. Recent results Unless there is a sudden process change near the sintering completion point, the pallet is usually based on the deviation from the target position of the sintering completion point, which is close to the target sintering completion point and predicted from the exhaust air temperature. Modify the speed, but before ignition, that is, if the freshly charged raw material has extremely poor air permeability,
Based on the deviation of the sintering completion point predicted based on the air permeability before ignition from the target position, the pallet speed is reduced at an early stage to prevent unburned residue in accordance with the deterioration of the air permeability. Modify pallet speed.

In the above control, the sintering completion point predicted from the exhaust air temperature is compared with the actual sintering completion point, and if the difference is more than a predetermined value, the predicted sintering completion point is abnormal. Considering this, the predicted value is optimized by replacing it with the predicted value calculated based on the actual sintering completion point so far. Further, in the above process, when it is determined to increase the pallet speed, if the exhaust air temperature at the sintering completion point where the exhaust air temperature is the maximum temperature is equal to or lower than the predetermined value, the calorific value of the sintering bed is insufficient. Therefore, the increase in the pallet speed is stopped, and the unburned residue (sintering failure) that may occur due to the increase in speed is suppressed.

[0011]

Embodiments of the present invention will be described with reference to the drawings. First, the structure will be described. As shown in FIG. 1, the raw material 2 is supplied into the feed hopper 1, and the raw material 2 is placed on the pallet 3 from the gate of the feed hopper 1 via the drum feeder 14. It can be placed. The pallet 3 can be moved in the longitudinal direction of the sintering machine by a drive unit 4 provided on the ore feeding side, and the drive unit 4 is drive-controlled by a drive control unit 12. Below the pallet of the sintering machine, a plurality of air boxes 5 are arranged along the longitudinal direction, and each air box 5 communicates with a main air exhauster 7 via a dust collector 6.
A thermometer 8 for measuring the exhaust air temperature is connected to each of the air boxes 5, and the exhaust air temperature measured by the thermometer 8 can be supplied to the sintering point control device 13.

An ignition furnace 9 is provided at a position separated from the ore supply hopper 1 on the mine ore side by a predetermined distance so that the surface of the raw material 2 placed on the pallet 3 can be ignited. Further, a pressure gauge 10 and a flowmeter 11 are installed in the wind box 5 on the most ore side, so that the ventilation resistance, which is the air permeability, can be measured. Further, the sintering point control device 13 predicts the sintering completion point from the exhaust air temperature and the air permeability, and controls the speed of the pallet 4 via the drive control device 12 and the drive device 4 based on the prediction.

In the above structure, the raw material 2 is charged from the feed hopper 1 into the pallet 3 through the drum feeder 14, and when the raw material 2 is moved right below the ignition furnace 9, the surface of the raw material 2 is ignited by the ignition furnace 9. To be done. The ignited raw material 2 is
When the pallet 3 is moved toward the mine ore side by the drive unit 4, the main air blaster 7 is operated, whereby air is sucked from the upper side to the lower wind box 5, and the firing unit 15 is moved from the upper side to the lower side. To move.

At this time, the exhaust air temperature is measured by the thermometer 8 installed in each wind box 5. The transition of the exhaust air temperature in the transport direction of the exhaust air temperature is shown by A in FIG. The speed of the pallet 3 that conveys the raw material 2 is controlled as shown in FIGS. 2 and 3 so that the sintering completion point B reaches the target position. For this reason, the air permeability of the raw material before ignition is the pressure gauge 1 arranged in the wind box 5 closest to the mine.
0 and the flow meter 11 measure each value, and the measured values are supplied to the sintering point controller 13. In the sintering point control device 13, the ventilation resistance is obtained from the input pressure value and flow rate value, and the sintering completion point is predicted by the ventilation resistance value (hereinafter referred to as the first predicted value). Further, the temperature of the exhaust air that has passed through each wind box 5 is measured by the thermometer 8 and the temperature signal is supplied to the sintering point control device 13.

The sintering point control device 13 obtains the current position of the sintering completion point B from the input temperature distribution, and
The position of the rising portion C of the temperature distribution is detected, and the sintering completion point is also predicted from the exhaust air temperature and position at the rising portion C (hereinafter referred to as the second predicted value). In addition to the first and second predicted values, the sintering point control device 13 determines that the measured values monotonically increase or monotonically increase in time series from the transition of the three latest measured values at the sintering completion point. If it is decreasing, the value calculated by the following formula is used as the simple predicted value, and the simple predicted value = current value + α- (current value-previous value) (α is a correction parameter and is a value of 0 to 1). In other cases, the simple prediction value = current value is set (step 1).

The speed of the pallet is adjusted according to the following procedure with each of the predicted values below to bring the sintering completion point closer to the target position. First, in order to respond to sudden process changes, it is checked whether the current actual sintering completion point is within the upper and lower limits of the target value, and the current actual sintering completion point exceeds the upper or lower limit value. If so (step 2), since the current value and the target value have changed significantly, the value obtained by subtracting the target value from the current measured value is set as the deviation (step 6).

Next, when the current actual sintering completion point is within the predetermined range, the second predicted value is checked, and the difference between the second predicted value and the current actual sintering completion point is predetermined. If it exceeds the allowable range (step 3), there is a high possibility that the second predicted value is an abnormal value, so the simple predicted value is set as the second predicted value (step 4). Next, it is checked whether the first predicted value is within a predetermined allowable range, and when the first predicted value is outside the allowable range and is larger than the second predicted value, the air permeability of the raw material is extremely high. Since the bad state is shown (step 5), the first predictive value is used for the control, the first
The predicted value-target value is taken as the deviation (step 7).

In other cases, the current actual sintering completion point has not changed significantly from the target value, the air permeability has not deteriorated extremely, and no large disturbance has occurred. Second value based on the second predicted value with good value accuracy
The predicted value-target value is used as the deviation (step 8). Next, the action amount (pallet speed change amount) is obtained by multiplying the deviation obtained on the basis of the present value, the first predicted value or the second predicted value by a predetermined correction value K (step 9). ).

If the action amount is within a predetermined range,
Do not change the pallet speed as a dead zone (Step 1
0) In addition, when the amount of action is negative, that is, when speed-up is requested (step 11), whether the calorific value of the sintering bed is insufficient or not, the exhaust air temperature is the highest value. The temperature of the exhaust air to be measured is measured. If the temperature is below a predetermined lower limit value, the calorific value of the sintering bed is insufficient (step 1
1) If the pallet speed is increased, unburned residue will occur, so the pallet speed is not increased. In cases other than the above, the pallet speed is increased or decreased according to the action amount (step 12). The acceleration or deceleration of the pallet is decelerated if the predicted sintering completion point is on the mine ore side, and is accelerated on the ore side.

The above treatment is performed every predetermined time, for example, every 5 minutes, and the pallet speed is adjusted to bring the sintering completion point close to the target value. With the above control, the second with high prediction accuracy
While adjusting the pallet speed based on the predicted value, a state in which the air permeability of the raw material that cannot be dealt with at the time of detecting the second predicted value is extremely poor, that is, a large disturbance is detected by the first predicted value and the first predicted value is detected. Handle pallet speed according to value early.

By comparison with the control of the sintering completion point based only on the second predicted value by experiments, it was confirmed that the standard deviation of the variation of the actual sintering completion point was reduced from 6% to 3%. As a result, the target value of the sintering completion point can be set larger by 3%, and the binder (auxiliary material such as quick lime) used for the purpose of improving the air permeability of the raw material can be reduced.

In the above embodiment, the rising point of the exhaust air temperature is detected and the exhaust air temperature at the rising portion is measured in order to obtain the second predicted value, but the rising point is determined by experience. If possible, the second predicted value may be predicted from the exhaust air temperature of the wind box at the fixed position.

[0023]

As described above, in the method for controlling the sintering completion point in the sintering machine of the present invention, the variation in the actual sintering completion point becomes smaller than the conventional one, and the raw material The amount of the binder (auxiliary material such as quick lime) used for the purpose of improving ventilation was reduced.

Further, by checking the heat quantity state of the sintering bed to increase the pallet speed, it is possible to reduce the unburned residue caused by the low heat quantity.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a sintering machine according to the present invention.

FIG. 2 is a flowchart for obtaining a deviation for correcting a pallet speed.

FIG. 3 is a flowchart for determining whether or not to correct a pallet speed and a correction based on the deviation.

[Explanation of symbols]

 1 Mining hopper 2 Raw material 3 Pallet 4 Drive device 5 Wind box 8 Thermometer 9 Ignition furnace 10 Pressure gauge 11 Flow meter 12 Drive controller 13 Sintering point controller

Claims (3)

[Claims] 1. A sintering completion point for controlling the pallet speed based on the sintering completion point predicted from the exhaust air temperature measured in each air box in the downward air intake sintering method to bring the sintering completion point closer to the target position. In the control method, when the deviation of the latest actual sintering completion point from the target position is outside the predetermined range, the pallet speed is corrected based on the deviation, and the deviation is within the predetermined range, and the ignition furnace The air permeability of the raw material measured in the previous wind box is lower than a predetermined value, and the sintering completion point predicted from the air permeability is on the mine ore side than the sintering completion point predicted from the exhaust temperature. In this case, the sintering completion point control method in the sintering machine is characterized in that the pallet speed is corrected based on the deviation of the sintering completion point predicted from the air permeability with respect to the target position. 2. When the deviation of the sintering completion point predicted from the exhaust air temperature with respect to the actual sintering completion point is not less than a predetermined range, the sintering completion point predicted from the exhaust air temperature is set in advance as the current sintering completion point. The sintering completion point control method for a sintering machine according to claim 1, wherein the actual sintering completion point is replaced with a value predicted from a transition tendency of the actual sintering completion point to date. 3. The pallet acceleration is stopped when the temperature of exhaust air passing through the air box at the sintering completion point is equal to or lower than a predetermined lower limit value. Sintering completion point control method in a sintering machine.