JPH0587463A - Production of sintered ore - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing sintered ores by means of a DL type sintering machine in which the quality of sintered ores is improved. CONSTITUTION:One method of manufacturing sintered ores is to seek the position (abbreviated as BRP) in the direction of the length of a sintering machine 1 at which the temperature of exhaust gas becomes set temperature as known from a temperature distribution curve for a wind box below a pallet in the direction of the length of the sintering machine and to seek the sintering time to reach the BRP from the distance from the ignition furnace to the BRP and the course taken by the pallet speed. The height of charged raw materials for sintering is controlled based on the deviation of the sintering time and a target sintering time and the amount of the charging action taken in the past. Since a change in the permeability due to the physical characteristics of the raw material, etc., is calculated from the sintering time up to the BRP and according to the value of change the quantity of charging is controlled, the quality of the sintered ore is stable and the production quantity and strength are thereby improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sinter production method for improving the quality of sinter in a DL type sintering machine.

[0002]

2. Description of the Related Art When manufacturing a sintered ore with a DL type sintering machine, various operating techniques have been developed and implemented in order to improve the quality of the sintered ore and the product yield. Using the method used for a long time, the exhaust gas temperature in the machine length direction of the sintering machine is measured, and the distribution of the exhaust box temperature (usually one exhaust gas temperature of the suction branch pipe of each air box is measured) is plotted as a quadratic curve. The quadratic curve formula is obtained by approximating to, and the wind box position (sintering end point, B
(Abbreviated as TP)), and the pallet speed is controlled so that the sintering end point becomes a preset set position.

In this method, the amount of shrinkage increases as the sintering completion layer approaches the slag ore, and as a result, air leaks due to cracks in the sintering completion layer and air leaks between the sidewall and the sintering completion layer increase. However, since this is not uniform in time, the fluctuation of the exhaust gas temperature on the mine ore side becomes large. For this reason, even if there is no change in the firing state of the sintering completed layer, the BTP changes and the pallet speed changes, which may rather deteriorate the quality of the sintered ore.

As a method proposed to solve the above problems, for example, as in Japanese Patent Laid-Open No. 60-13032, transition of exhaust air temperature of each wind box measured in each width direction according to movement of raw material. Detects the firing point for each width direction,
A method of calculating an average firing point in the width direction from the detected value and adjusting the pallet speed so that the calculated value becomes a predetermined target value, and a primary sintering machine as disclosed in JP-A-62-149821. A method for controlling the pallet speed of the sintering machine so that the crushing energy measuring device is provided on the single spike roll of the crusher so that the obtained crushing energy has a constant value, and as in JP-A-2-88724, There is a method of detecting the firing completion point based on the exhaust gas temperature of the box, measuring the dust concentration in the slag of the sintering machine, and controlling the position of the firing completion point according to the change in the measured value.

[0005]

However, the method of controlling the pallet speed by the average firing point in the width direction as disclosed in Japanese Patent Laid-Open No. 60-13032 is to measure the exhaust gas temperature by the suction branch pipe of the conventional wind box. Although the accuracy is slightly higher than that of the method in which the firing completion point is obtained, it is still not possible to eliminate the influence of leakage of air and the occurrence of control time delay due to the size of the heat capacity of the grate.

As disclosed in Japanese Patent Laid-Open No. 62-149821, the method of determining the crushing energy in the single spike roll of the primary crusher of the sintering machine and controlling the firing end point is the correlation between the crushing energy and the powder ratio after crushing. The sinter ore quality varies greatly due to the large variability. The method of measuring the dust concentration in the mine ore as described in Japanese Patent Application Laid-Open No. 2-88724 has a problem in that the dust concentration changes quadratically with respect to the rate of occurrence of returned ore, so that only rough control is possible. is there.

[0007]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and a machine length that the exhaust gas temperature becomes the set temperature from the pallet downwind box temperature distribution curve in the machine length direction of the sintering machine. The position in the direction (abbreviated as BRP) is calculated, and BR is calculated from the distance from the ignition furnace to BRP and the progress of the pallet speed.
Sintering control characterized by determining the firing time until reaching P and controlling the charging height of the sintering raw material based on the deviation between the firing time and the target firing time and the charging action amount taken in the past. Is the way.

[0008]

[Action]

(1) At the starting point of the wind box temperature rise within the rising range of the parellet lower wind box temperature (hereinafter simply referred to as the wind box temperature) in which the amount of air leakage from the wind box is small and the cracks in the sintering completion layer are not so large. The firing time up to the near BRP well reflects the change in the air permeability of the sintering raw material layer, and a highly accurate charging action amount can be obtained.

(2) The charging action amount obtained from the deviation between the above firing time and the target firing time is the variation due to disturbance (changes in raw material properties, granulation conditions, etc.) and the past charging action amount. However, if the charging action amount obtained this time is taken as the action amount as it is, the charging action amount taken in the past is doubled, which is an over-action. In the present invention, since the charging action amount taken in the past is subtracted from the charging action amount obtained this time, it is possible to take an appropriate action corresponding to the newly generated disturbance.

[0010]

EXAMPLES Examples of the present invention will be described in detail below. FIG. 1 is a block diagram illustrating a control method of the present invention, and FIG. 2 is a computation block diagram of a computing unit. The sintering raw material of the surge hopper 2 is loaded onto the pallet 7 which moves toward the ignition furnace 6 via the sloping chute 5 by the roll feeder 4 while the cutting amount is adjusted by the cutting gate 20.

The sintering raw material 8 charged in the pallet 7 forms a charging ridge 9 under the sloping chute 5, and the upper surface is formed by a cut plate (not shown) provided under the sloping chute by the movement of the pallet 7. Are leveled, and the upper surface is ignited by the ignition furnace 6.

On the other hand, below the pallet 7, a large number of air boxes 10 are provided in the machine length direction of the sintering machine 1.
Since the atmosphere is sucked in through, the combustion zone 11 generated on the upper surface descends as the pallet moves, and reaches the lower end of the sintering completion layer before the mine ore portion 12. A sintered sintering completion layer 13 is formed on the upper layer of the combustion zone 11, and the total height of the sintering raw material layer in the ore discharge section 12 becomes the sintering completion layer 13 and is discharged.

Thermometers (thermocouple thermometers) 14 are arranged at three points in the width direction of each wind box 10 below the pallet 7 in five rows in the machine length direction, and these measured values are transmitted to the calculator 15. (Step 31). Further, the pallet speed obtained from the rotation speed of the drive motor 17 of the drive sprocket 16 of the sintering machine, the rotation speed of the roll feeder 4, and the opening of the cutting gate 3 of the roll feeder are transmitted to the calculator 15 (step 32). FIG. 4 is an explanatory view of the cutout gate of the surge hopper, and the cutout gate 20 is the main gate 2
1 and a main gate 21 are divided into five sub-gates 22 arranged in the width direction. The main gate 21 is a rack 2
3 and the gear 24, the child gate 25 is the electric cylinder 2
It is adapted to be opened / closed by the drive unit 6.

Five rows of ultrasonic level meters 18 are provided in the width direction of the charging pile so as to face the slope of the charging pile 9 formed under the sloping chute 5, and these measured values are also stored in the calculator. It has been transmitted (step 33). Five ultrasonic level meters transmit at the same time, but by selecting the shortest value among the reflected waves, interference from other ultrasonic level meters is prevented.

Next, the contents of the calculation performed by the calculator 15 will be described. An exhaust gas temperature distribution curve (approximate to a quadratic curve) was obtained for each column from the exhaust gas temperature under the pallet, and B
From the set temperature of RP (for example, 250 ° C.), the position where the exhaust gas temperature of each row reaches the set temperature, that is, BRP is obtained,
From these, the average BRP is obtained (step 34).

Generally, the pallet speed PS changes with time t as shown in FIG. 3, and the distance x (m) from the ignition furnace to the BRP is several if the pallet speed at time t is PS (t). Required by 1. The firing time t is t that satisfies the expression 1. The x in the equation 1 is a function of BRP and is represented by the equation 2. Here, A and B are constants.

[0017]

[Equation 1]

[0018]

[Equation 2]

PS (t) in the equation 1 is a time function of the past pallet speed, but since the data actually accumulated is a discrete system for each minute, PS (t) can be easily obtained. I can't.

Therefore, if the data for each minute is used as a representative value for the one minute, and the equation 1 is transformed into the following equation 3,

[0021]

[Equation 3]

## EQU2 ## t can be obtained from equation 4. Then, the required firing time τ (min) can be expressed by Equation 5.

[0023]

[Equation 4]

[0024]

[Equation 5]

Δt in the equation (5) is obtained as follows.
The firing time τ is t ≦ τ ≦ t + 1. (T + 1)
The pallet speed from the minute before to the minute before is PS _t , and the moving distance Δx during this time is represented by Formula 6.

[0026]

[Equation 6]

Therefore, the moving time is expressed by the equation (7).

[0028]

[Equation 7]

Therefore, the firing time τ (min) can be obtained from the equation 8 from the equations 4, 5, and 7.

[0030]

[Equation 8]

The firing time from the ignition furnace to the average BRP is calculated from equation 8 (step 35). Based on the instrumentation Iriyama height This calcination was time and received, using the number 9 seek dumping actions amount .delta.h _l (step 36).

[0032]

[Equation 9]

The first term of the curly braces of the equation (9) is the charging action amount including the disturbance due to the deviation between the firing time and the target firing time, and the second term is the past charging action amount. The subscript l is the time (current) at which the charging action amount is calculated,
The subscript l-m represents a unit time × m minutes before the present time.
The parameter J in the finite settling is a constant for weighting the deviation of the firing time at the past time, and the parameter K
Is a constant for weighting the charging action amount at the past time. The unit time is usually 15 minutes, but other times may be used. A simple calculation example of Expression 9 is shown as Expression 10.

[0034]

[Equation 10]

In this example, J (current): 70%, J (1
5 minutes before): 30%, K (15 minutes before): 1.0, K
(30 minutes ago): 0.3 is weighted. Also,
G = 1 / 3.0 (mm / sec). The obtained charging action amount is transmitted to the drive device of the cutting gate 20 and the charging pile height is controlled.

Table 1 shows a comparison between the method of the present invention and the conventional method in terms of production specifications. From this, it is understood that the production amount and the cold strength are improved by the method of the present invention as compared with the conventional method.

[0037]

[Table 1]

[0038]

According to the present invention, since the change in the air permeability due to the change in the raw material properties and the like is calculated from the change in the firing time until reaching BRP, and the charging amount is controlled according to the change, Compared with the method, the quality of the sinter is stable, which has the effect of improving the production volume and strength.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a control method of the present invention.

FIG. 2 is a calculation block diagram of a calculator.

FIG. 3 is a graph showing changes in pallet speed with time.

FIG. 4 is an explanatory diagram of a cutout gate of a surge hopper.

[Explanation of symbols]

 9 Charging Mountain 10 Wind Box 11 Combustion Zone 13 Sintering Complete Layer 14 Thermometer 15 Calculator 17 Sprocket Drive Motor 18 Ultrasonic Level Meter 20 Cutting Gate

Claims (1)

[Claims] 1. A position (abbreviated as BRP) in the machine direction where the exhaust gas temperature reaches a set temperature is obtained from a pallet downwind box temperature distribution curve in the machine direction of the sintering machine, and the distance from the ignition furnace to the BRP and the pallet speed. It is characterized in that the firing time from the lapse of time to BRP is obtained, and the charging height of the sintering raw material is controlled based on the deviation between the firing time and the target firing time and the charging action amount taken in the past. Sintered ore manufacturing method.