JP2658748B2 - Operating method of sintering machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation method for maintaining a stable operation while maintaining a production amount near a target value in a DL sintering machine.

[0002]

2. Description of the Related Art There are various methods for controlling the sintering point of a DL-type sintering machine. The main examples are as follows.

A first example is disclosed in Japanese Patent Publication No. 59-37729, in which a firing point is obtained by a specific mathematical expression having a temperature of an exhaust air as a factor, and the rotational speed of a main exhaust fan is determined based on this. (Hereinafter referred to as Conventional Example 1).

A second example is described in Japanese Patent Application Laid-Open No. 3-249139, in which a vector intensity is obtained from a temporal change of exhaust air temperature and a pallet speed is adjusted based on the vector intensity (hereinafter referred to as a conventional example). 2).

A third example is disclosed in Japanese Patent Laid-Open Publication No. Hei 3-10427. If the expected control error of the firing point is within an allowable range, the target value of the production amount is maintained and the target value is set outside the allowable range. Then, it is a method of adjusting the pallet speed so that the control error of the firing point falls within an allowable range (hereinafter referred to as Conventional Example 3).

[0006]

In the first conventional example, the pallet speed is set in accordance with the target production amount, and the control of the firing point is adjusted by the rotation speed (air volume) of the main exhaust fan. However, it is generally difficult to adjust the rotational speed (air volume) of the main exhaust fan with high responsiveness due to the characteristics of the equipment, and it is not preferable to adjust the rotation speed in a short cycle in operation. Therefore, there is a problem that the controllability of the baking point is deteriorated as compared with the adjustment of the pallet speed.

Conventional Example 2 focuses on the fact that the vector strength obtained from the temporal change of the exhaust air temperature in each wind box of the sintering machine is closely related to the cold strength of the sinter, and this is the basis. The pallet speed is adjusted so that the vector intensity becomes a predetermined value. However, there is a problem that it is difficult to maintain the target value of the production amount by simply adjusting the pallet speed because the adjustment of the pallet speed leads to the fluctuation of the production amount.

In prior art 3, a pallet speed is adjusted such that an allowable error is provided at the firing point and the firing point falls within a predetermined allowable error range while maintaining the target value of the production amount. However, depending on the operation state, the target value of the production amount may not be maintained unless the tolerance of the firing point is made large. For this reason, there is a problem that there is a limit in achieving both the stabilization of the firing point and the maintenance of the target value of the production amount.

The present invention has been made in view of the above circumstances, and proposes a method of operating a sintering machine that stabilizes a sintering point while suppressing medium- to long-term fluctuations in production volume.

[0010]

Means for Solving the Problems From the viewpoint of stabilizing the quality of sintered ore and preventing an increase in the amount of ore returned (deterioration of yield) due to an increase in the amount of unsintered ore, the sintering point is a medium to long term (time to It is necessary to stabilize not only in units but also in the short term (minutes). However, short-term stability is not very important for production, and shifts (every 8 hours)
It is only necessary that the required amount of sintered ore be produced by the end of the day. This is because charging of the sinter into the blast furnace is performed once through a buffer called an ore storage tank.

As described above, the sintering point is controlled more precisely with the pallet speed at which controllability with higher accuracy than the main exhaust air volume can be obtained. The present inventors have found that it is necessary to adjust the main exhaust air volume so that the pallet speed in a predetermined medium to long term becomes a value capable of obtaining a target production amount, while controlling the vehicle from a medium to long term perspective. It is.

That is, the present invention provides a sintering method for adjusting a pallet speed and a main exhaust air volume such that a sintering point detected from an exhaust air temperature of a sintering machine and a production amount measured by a production amount measuring device become predetermined values. In the operation method of the machine, the baking speed is predicted from the detected baking point, the packed layer thickness, the pallet speed, and the main exhaust air amount, and the pallet speed is adjusted based on the predicted value of the baking speed, and the measured production amount is calculated. An object of the present invention is to predict a production amount from a material balance equation from a packed bed thickness and a pallet speed, and adjust a main exhaust air amount based on the predicted value of the production amount.

[0013]

As a function of the present invention, a method of detecting a firing point and a method of calculating a pallet speed for controlling the firing point will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing the relationship between the firing point and the exhaust air temperature of each wind box. FIG. 2 shows the wind boxes and the positions of the exhaust air temperature measuring thermocouples arranged in them. FIG.

The raw material cut out from each raw material tank (not shown) is continuously palletized by rotating the roll hopper 3 from the surge hopper 2 so that the measured value of the raw material loading bulk meter 1 becomes a predetermined value. Is supplied on Great 5 The supplied raw material is conveyed to a mining part by moving a pallet while forming a packed layer 6 having a predetermined thickness. During this time, the surface of the packed bed 6 is ignited by the ignition furnace 7 installed near the ore supply point.

On the other hand, each wind box 8 is located below the pallet conveyance path.
Each of the wind boxes 8 serves as a suction port of combustion gas generated in the packed bed 6 and forcibly sucked by the main exhaust fan 9. A thermocouple 10 is provided in each wind box 8, and measures the temperature of the sucked combustion gas (exhaust air temperature). The exhaust air temperature is substantially constant until the combustion fronts 12-1 and 12-2 reach the pallet great 5, but starts to rise immediately before the arrival position, that is, the firing points 13-1 and 13-2. . The rise of the exhaust air temperature is as shown by the exhaust air temperature transition curves 14-1 and 14-2 of the wind boxes 8 measured in the pallet width direction according to the movement of the raw material, and their rising points 15-1 and 15-2. Can be regarded as firing points in respective portions in the width direction.

Based on the firing points thus detected, the average firing distance in the width direction (the distance from the ignition furnace to the firing point) is obtained by the following equation (1). The second term on the right side of Equation 1 is
This is a term for correcting an error caused by measuring the exhaust air temperature in the width direction only at two points.

[0017]

(Equation 1)

Here, Lffp: average firing distance in the width direction (m) Lffp1, Lffp2: firing distance (m) obtained from the firing point detected from the exhaust air temperature transition curve α: correction coefficient (−)

The average actual firing speed Vf between firing distances is:
From the relationship shown in FIG. 3, by using this firing distance, it can be obtained by Expressions 2 and 3.

[0020]

(Equation 2)

[0021]

(Equation 3)

Where Vf (-t): actual firing speed before tmin (m / min) PsB (-t): average pallet speed (m / min) between firing distances before tmin Ps (-t): Pallet speed measurement value before tmin (m /
min) h (-t): tmin before the filling layer thickness measurements (m) Lffp (-t): tmin before firing distance detection value (m) L _11: to the firing point detection value by the pallet velocity change varies Waste time (min) L ₁₂ : waste time (min) until the detected value of the sintering point changes due to a change in the thickness of the packed layer Tt: time required to move between sintering distances (min) (Tt is a value satisfying Equation 4)

[0023]

(Equation 4)

In addition, if there is no other disturbance, the firing rate changes almost in proportion to the main exhaust air volume shown in Equation 5.

[0025]

(Equation 5)

K: proportional coefficient Q: main exhaust air volume (Nm ³ / min)

Therefore, the firing rate is, for example,
Can be predicted by

[0028]

(Equation 6)

VfY (-t): Predicted firing speed (m / min) before t min Qs (-t): Main exhaust air flow set value (Nm ³ ) before t min
/ Min) Q (−t): measured value of main exhaust air volume before t min (Nm ³ /
min) L ₂ : Dead time (min) until the firing point detection value changes due to a change in the main exhaust air volume

Therefore, the pallet speed Psc for obtaining the target firing distance can be calculated by, for example, Equation 7 given the target firing distance.

[0031]

(Equation 7)

However, LffpA in Equation 7 is a firing distance target value.

Next, a method of calculating the main exhaust air amount for obtaining the target production amount will be described. First, the relationship between the production amount and the pallet speed can be expressed by Equation 8 using a material balance equation. Equation 8 can also be transformed into Equation 9 using the relationship shown in FIG.

[0034]

(Equation 8)

[0035]

(Equation 9)

Here, Pd: production amount (T / H) ζ: yield (-) ρ: density (T / m ³ ) W: pallet width (m) h: packed layer thickness (m) Ps: pallet speed ( m / min) Lffp: firing distance (m) Vf: firing speed (m / min) Here, the pallet width W in Equation 8 is a facility constant, and the yield ζ and density ρ usually do not largely fluctuate. Constant handling is possible.

From the above, the production quantity can be predicted by, for example, the following equation (10).

[0038]

(Equation 10)

Here, PdY (−t): the predicted value of the production amount before t min (T / H) Pd (−t): the measured value of the production amount before t min (T / H) Pss (−t): t min before the pallet speed setting value (m / min) L _31: dead time to production amount measurement value by the filling layer thickness change is changed (min) L _32: a pallet speed change to production amount measurement value changes Dead time (min) TI ₁ : Integration time (min) for data smoothing

Further, since the relationship between Expressions 5 and 9 and the target value of the firing distance are usually constant values, the production amount can be controlled by adjusting the main exhaust air amount. The main exhaust air amount Qc can be calculated by, for example, Expression 11.

[0041]

[Equation 11]

PdA: target production value (T / H) TI2: integration time (min) for data smoothing

[0043]

FIG. 4 is a schematic diagram showing an example of the configuration of an apparatus for carrying out the method of the present invention. In the figure, 18 is a packed layer thickness gauge,
19 is a production amount measuring device, 20 is a firing distance calculating device, 21
Is a firing point control arithmetic unit, 22 is a manual setting device, 23 is a pallet speed detection and adjustment device, 24 is a production amount control and arithmetic device, and 25 is a main exhaust air volume detection and adjustment device. Other reference numerals are the same as those shown in FIG.

The firing distance calculating device 20 inputs the exhaust air temperature measured by a thermocouple installed in each wind box 8, detects the firing point from the transition of the exhaust air temperature, and calculates the firing point in the width direction according to Equation 1. Is calculated, and the obtained value is output to the firing point control arithmetic unit 21.

The firing point control arithmetic unit 21 includes a firing distance Lffp input from the firing distance arithmetic unit 20 and the manual setting unit 2.
2, the calcination distance target value LffpA input from 2, the filling layer thickness measurement value h input from the filling layer thickness gauge 18, the pallet speed measurement value Ps input from the pallet speed detection adjustment device 23, and the main exhaust air volume detection adjustment device 25. Based on the measured value Q and the set value Qs of the main exhaust air volume, the above equations 2, 3, 6, and 7 are obtained.
Pallet speed Ps for obtaining the target firing distance
Calculate c. Then, the calculated pallet speed P
The pallet speed is adjusted by giving sc as the set value Pss of the pallet speed detection adjustment device 23.

On the other hand, the production control arithmetic unit 24 includes a production measurement value Pd input from the production measurement device 19, a production target value PdA input from the manual setting device 22, and a packed bed thickness meter 1.
8, the pallet speed measurement value Ps and the set value Pss input from the pallet speed detection adjustment device 23 and the main exhaust air volume measurement value Q input from the main exhaust air volume measurement device 25. , The main exhaust air amount Qc for obtaining the target production amount is calculated. Then, the calculated main exhaust air volume Qc is used as the main exhaust air volume detection adjusting device 25.
And the main exhaust air volume is adjusted.

In this case, the adjustment period of the main exhaust air volume should be set so as to avoid interference with the pallet speed operation while taking into consideration the stabilization of the entire raw material on the sintering machine (generally, a short period of 1 to 5 minutes). Although the same cycle as the pallet speed adjustment cycle is not preferable) and obtaining the target production amount (short cycle is more preferable), it is usually longer than the pallet speed adjustment cycle. Is preferably 10 minutes to 1 hour.

Next, the results of operation of the present invention applied to an actual machine will be described. Table 1 shows the values obtained by carrying out the method of the present invention and the values obtained by carrying out the conventional method 3 together for easy comparison. In the conventional method 3, only the pallet speed is adjusted so that the firing point detected from the exhaust air temperature and the production amount measured by the production amount measuring device become a predetermined value. As is evident from Table 1, the implementation of the method of the present invention reduced both the production rate and the variation (standard deviation) of the firing distance, confirming that stable operation was achieved.

[0049]

[Table 1]

[0050]

As described above, the method of the present invention comprises:
By controlling the firing point at a pallet speed that provides higher controllability than the main exhaust air volume, and adjusting the medium- to long-term pallet speed with the main exhaust air volume to achieve a target production volume, It is possible to stabilize the sintering point while suppressing fluctuations in the production amount of the sintering machine, and contribute to the stable operation of the sintering machine.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a relationship between a firing point and an exhaust air temperature of each wind box.

FIG. 2 is a plan view showing an arrangement of a wind box and a thermocouple for measuring exhaust air temperature.

FIG. 3 is an explanatory diagram showing a relationship between a burning speed and a pallet speed in a steady state.

FIG. 4 is a schematic diagram showing an example of a device configuration for implementing the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bulk gauge for charging raw material 2 Surge hopper 3 Roll feeder 4 Raw material 5 Great of pallet 6 Packing layer 7 Ignition furnace 8 Wind box 9 Main exhaust fan 10 Thermocouple 12-1,12-2 Combustion front 13-1,13-2 Firing point 14-1, 14-2 Exhaust air temperature transition 15-1, 15-2 Exhaust air temperature rise point 18 Packed bed thickness gauge 19 Production amount measuring device 20 Firing distance calculating device 21 Firing point control calculating device 22 Manual setting device 23 Pallet speed detection and adjustment device 24 Production volume control arithmetic device 25 Main exhaust air volume detection and adjustment device Vf Baking speed (m / min) Ps Pallet speed (m / min) h Packing layer thickness (m) Lffp Baking distance (m)

Claims (1)

(57) [Claims] 1. A method of operating a sintering machine for adjusting a pallet speed and a main exhaust air volume such that a firing point detected from an exhaust air temperature of the sintering machine and a production amount measured by a production amount measuring device become predetermined values. In, the baking point is predicted from the detected baking point, the packed bed thickness, the pallet speed and the main exhaust air amount, and the pallet speed is adjusted based on the predicted value of the baking speed, and the measured production amount and the packed bed thickness are A method for operating a sintering machine, comprising: predicting a production amount from a pallet speed and a mass balance equation, and adjusting a main exhaust air amount based on the predicted value of the production amount.