JPH03177787A - Reduction of sintering nonuniformity of sintered ore - Google Patents

Abstract

PURPOSE:To permit the delicate control of nonuniform sintering in widthwise direction by a method wherein the action amount of layer thickness is determined based on a relative relation between the difference of widthwise layer thickness of a pallet and the difference of window box temperature of widthwise ore discharging unit. CONSTITUTION:A process computer 10 samples the thickness of layer Hij of every rows of pallets and the window box temperature Tij of an ore discharging unit to obtain average values Hi, Ti in every widthwise directions (every rows) of the pallet as well as the average value of all rows and operate differences DELTAHi, DELTATi from the average values of all rows while the operated valaues are preserved in a file. Upon arriving at a learning period, the regression analysis of the differences DELTATi, DELTAHi is effected in every widthwise directions (in every rows) of the pallet while employing data in the degree of nearest 4 hours. When the relative coefficient gamma i of an obtained regression straight line is higher than a reference value gamma o, the value of Ki is renewed from the previous value of Ki by the inclination of the regression straight line. The layer thickness setting value Hisv of next time is operated while employing the values of Ki, the nearest temperature difference DELTATi, a layer thickness average value Hi in every rows and a microcomputer 11 controls the opening degrees of sub-gates in respective rows through PID control so that the operated value becomes DELTAHisv.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method for reducing uneven burning of sintered ore in a Dwight Lloyd sintering machine.

[Prior art 1] In a Dwight Lloyd-type moving grid sintering machine, when the sintered state of the sintered ore packed bed on the pallet is observed at the sintering machine waste ore measuring end, it is found that the width direction of the packed bed on the pallet is There are parts where firing has progressed sufficiently and parts where firing has not progressed sufficiently (unfired parts), and a so-called uneven firing phenomenon may be observed.

When such uneven burning in the width direction occurs, the quality of the sintered ore (falling strength, particle size, chemical composition, etc.) deteriorates and varies, and the rate of return ore generation increases. As a result, there are many negative effects on the production of sintered ore, such as a decrease in production.

Therefore, it is necessary to measure the wind box temperature Ti in the pallet width direction in the sintering machine ore discharge section or the red zone cross section HzRi of the sinter cake in the ore discharge section, and adjust the feed rate of raw materials in the pallet width direction based on the results. is being carried out. For example, these are JP 50-40361, JP 51-23365, and JP 60-10.
This is disclosed in Publication No. 096 and the like.

FIG. 3 is a schematic diagram for explaining this, and is an explanatory diagram in which a measurement and control system is added to a perspective view of the main parts of the sintering machine.

In FIG. 3, 1 is an ore feeding hopper, 2 is a drum feeder for supplying raw materials, 3 is a main gate whose opening degree is set according to production volume, and 4 is a pallet.

A split operation type adjustment gate 5 is provided to finely adjust the feed amount in the width direction of the drum feeder 2, and this adjustment gate 5 is driven by a power cylinder 6. The layer thickness Hi of the raw material layer A on the pallet is measured with an ultrasonic level meter 7. In addition, the measured values of the wind box thermometer 8 in the ore discharge section and the observation data of the fTV camera 9 that measures the red zone cross section of the sinter cake in the ore discharge section are input to the upper process computer 10, and the output of the upper process computer 10 is The data is input to the lower-order microcomputer 11, and necessary control is performed.

In the conventional technology, the wind box temperature Ti of the ore discharge section or the red zone cross section H2Ri of the sinter cake in the ore discharge section is continuously measured, and the process computer 10 measures the layer thickness deviation in the width direction △ to eliminate variations in Ti and H2Ri. Hisv
That is, the difference between the average layer thickness and the measured layer thickness is set at regular intervals. The microcomputer 11 calculates the indicated value △ from the process computer based on the measurement result of the layer thickness Hi.
The power cylinder 6 is driven to control the opening degree of the adjustment gate 5 so as to match Hisv. The average layer thickness H is managed so that the supply amount (discharge amount) is controlled by controlling the rotation speed of the drum feeder 2, and the set layer thickness is achieved.

Generally, the layer thickness ΔHisv is set for each width direction mainly in order to smooth the ore discharge part temperature Ti, but how to give this set value was the most difficult point in this control.

[Problem to be solved by the invention]

Layer thickness Hi by width direction and ore discharge part wind box temperature Ti
We investigated the relationship over four days, and this is shown in Figure 4.
As shown in Fig. 4, there is a negative correlation between the layer thickness Hi and the temperature Ti, so for rows with good ventilation and high temperature Ti, the layer thickness Hi can be increased, and for the opposite row, the layer thickness Hi can be lowered. , the relationship between the layer thickness Hi and the temperature Ti changes depending on the location and time. In FIG. 4, the measured values are entered for each of No. 1 to 5 gates, and the relationship therebetween is shown by five straight lines. In this way, the relationship between the layer thickness Hi and the temperature Ti changes depending on the location and time. Therefore, a system can be considered in which the correlation between the layer thickness Hi and the temperature Ti is determined for each column based on the data of the most recent several hours, and the action width □ of the layer thickness Hi is determined based on the slope of the straight line.

However, in addition to the five-layer thickness Hi, there are various factors that affect the wind box temperature Ti of the ore discharge section, such as the packing density of the sintering raw material on the pallet, particle size composition, moisture content, clogging of the pallet, air leakage, etc. Since factors are involved, a clear relational expression is rarely obtained even if the correlation between the layer thickness Hi and the temperature Ti is investigated using data of several hours.

Therefore, at present, the temperature Ti for the amount of change in the layer thickness Hi is
It is assumed that the width of change in is constant, and the layer thickness deviation ΔHi is set and controlled for each width direction. In order to perform finer control to eliminate variations in the temperature Ti in the width direction, it is necessary to adjust the layer thickness Hi and the temperature T.
It is necessary to review the relationship with i for each column every few hours.

[Means to solve the problem]

However, even if the relationship between the absolute value Hi of the layer thickness and the absolute value Ti of the wind box temperature at the ore discharge portion was determined for each row, a good correlation could not be obtained due to the influence of other factors.

Therefore, in order to eliminate as much as possible the influence of factors other than Hi that affect Ti, the relationship between the widthwise layer thickness deviation ΔHi and the widthwise windbox temperature deviation ΔTi was determined. An example is shown in FIG. 2, and there was a very good correlation between ΔHi and ΔTi. The data is for the last 4 hours, and the data here is 30
Minute average value. Furthermore, the layer thickness Hi and the wind box temperature Ti of the ore discharge portion are made to correspond with each other with a time delay of about 30 minutes in consideration of the traveling time.

In this way, since there is always a good correlation between the width direction layer thickness deviation △Hi and the width direction windbox temperature deviation △Ti, a system that uses the slope Ki of this regression equation to determine the layer thickness action amount can be used. For example, the present invention was completed based on the finding that more fine-grained uneven firing in the width direction can be controlled.

The present invention relates to a method of operating a Dwight Lloyd sintering machine,
The temperature distribution in the pallet width direction in the ore discharge side wind box was measured, and the distribution of the deviation △Ti from the average temperature of this temperature was determined, while the layer thickness distribution of the packed bed in the pallet width direction on the ore feeding side was measured. , the deviation of this layer thickness from the average value △Hf
The width of change in △Ti with respect to the amount of change in △Hi at the corresponding position in the width direction is estimated, and the layer thickness distribution is controlled based on the estimated value in accordance with the target value of the layer thickness in the width direction of the pallet. This is a method for reducing unevenness in sintered ore.

[Operation] The system configuration itself used to implement the present invention is the same as the conventional technology shown in FIG. The present invention is a method for setting layer thickness deviation ΔHisv in a process computer,
A schematic flowchart is shown in FIG.

FIG. 1 shows a control system for making the wind box temperature Ti of the ore discharge section uniform at five forces in the pallet width direction.

In order to match the data, the layer thickness Hi for each column for each pallet
j, sample the wind box temperature T i,j of the ore discharge section. When the data for the specified number of pallets n is accumulated, average values Hi and Ti are calculated for each pallet width direction (for each column). Furthermore, the deviations from the average value of all columns △Hi, △Ti
Calculate column by column. ΔH1 and ΔTf data are saved within the file.

When the learning cycle is reached, a regression analysis of ΔTi and ΔHi is performed for each pallet width direction (for each row) using data for the most recent four hours. If the correlation coefficient γi of the obtained regression line is equal to or greater than the reference value 70, Ki is updated from the previous Ki using the slope of the regression line.

KL is defined for each column (i=1 to 5).

The next layer thickness setting value Hisv is calculated for each row using this Ki, the most recent ore discharge section windbox temperature deviation ΔTi for each row, and the average layer thickness value HL for each row. If the learning cycle (about every 2 hours) has not been reached, the KL before update and the latest △T
Hisv is calculated from i and Hi.

Although it is controlled by the rotation speed of the feeder 2, in this system, since the deviation from H is the control target, the layer thickness deviation set value ΔHisv is calculated in the pallet width direction. △Hisv for each column
The operating constraints are checked and instructions are given to the lower-level microcomputer. In the microcomputer, △His
The sub-gate opening degree of each column is PID controlled so that the opening degree of the sub-gate of each column is set to v.

The above control flow is repeated every time par 110 passes. n
can be set arbitrarily.

"Example" Rock length 58m, pallet width 3.5m, wind box 1
Using 5 DL type sintering machines, the production capacity is 8500 t/
day, layer thickness 630-6'60 mm, pallet speed 1
．． The invention was carried out under operating conditions of 8-2.2 m 7 minutes.

The following three types of operations were conducted under the same raw material conditions.

(1) No adjustment gate control The opening degree of the adjustment gate 5 is constant, and ventilation adjustment is performed only by changing the pallet speed and average layer thickness.

(2) With m adjustment gate control (conventional method) In order to smooth the gas temperature in the width direction of the pallet in the wind box 14 (the 14th wind box among 15 wind boxes), the opening of the adjustment gate 5 is control. The layer thickness deviation ΔHf5v is set assuming that the change in Ti with respect to the amount of change in the layer thickness Hi in the width direction is constant.

(3) With Fl adjustment gate control (method of the present invention) No. 14
In order to smooth the temperature (Ti) in the width direction of the pallet inside the window box, the adjustment gate is controlled according to the flow shown in FIG.

The operations (1) to (3) above were carried out for one week each, and the results shown in Table 1 were obtained.

By performing adjustment gate control, uneven baking in the pallet width direction was reduced, and the widthwise variation in wind box temperature was reduced.As a result, the average layer thickness and shutter strength were improved, and the return generation rate was reduced.

Even with the conventional control method, the reduction is 0.9 compared to the case without control.
Although the % return ore generation rate has decreased, the method of the present invention has further reduced the return ore generation rate by 0.7%, and the control method according to the present invention has enabled more fine-grained management of burnt unevenness. Furthermore, the strength of the product shutter was improved by approximately 0.3% compared to the conventional method due to the reduction in brittle sinter cake.

"Effects of the Invention" In the Dwight Lloyd sintering machine, the uneven burning method of the present invention enables quality control in the width direction of the pallet, which was difficult with conventional methods, and fine-grained pallets that take into account the influence of changes in raw material conditions over time. It becomes possible to control firing in the width direction, which has a great effect on improving the yield of sintered lumps and improving the strength of sintered ore.

[Brief explanation of drawings]

FIG. 1 is a flowchart for controlling uneven burning according to the method of the present invention.
Figure 2 shows the relationship between the layer thickness deviation ΔHi in the width direction and the windbox temperature deviation ΔTi in the width direction, Figure 3 is a block diagram showing the configuration of the uneven baking control system, and Figure 4 shows the relationship between the layer thickness Hi and the windbox temperature Ti. It is a graph showing a relationship. l...Ore supply hopper 2...Drum feeder 3...Main gate 4...Pallet 5...Adjustment gate 6...Power cylinder 7...Ultrasonic level meter 8...Ore discharge Wind box thermometer 9...ITV
Camera 10...Process computer 11...Microcomputer Kawasaki Steel Corporation

Claims (1)

[Claims] 1. When operating the Dwight Lloyd sintering machine, measure the temperature distribution in the pallet width direction in the ore discharge side wind box, determine the distribution of deviation ΔTi from the average temperature of the temperature,
On the other hand, measure the layer thickness distribution of the packed layer in the pallet width direction on the ore feeding side, and determine the distribution of the deviation ΔHi from the average value of the layer thickness,
It is characterized by estimating the change range of △Ti with respect to the change amount of △Hi at the corresponding width direction position, and controlling the layer thickness distribution in accordance with the target value of the layer thickness in the pallet width direction based on the estimated value. Method for reducing unevenness in sintered ore.