JPH01188636A - Method for controlling heat level of raw material for sintered ore - Google Patents

Abstract

PURPOSE:To simplify the adequate control of a heat level in compounded sintering raw materials by measuring the frequencies at which a high-temp. red hot zone appears in a method for photographing the section of sintered cake in the ore discharge part of a sintering machine by an IR camera. CONSTITUTION:The section of the sintered cake which is continuously calcined and moved is photographed by the IR camera 8 in the ore discharge part of a Dwight-Lloyd sintering machine 1 at the time of calcining the iron ore of a blast furnace charge by said sintering machine. The video thereof is analyzed by an image analyzing device 9 and the frequencies at which the high-temp. red hot zone above the prescribed temp. appears within unit time are measured. The compounding rate of the coke which is the sintering raw material is adjusted in accordance with the results of the measurement. The adequate control of the heat level in the compounded sintering raw materials 3 is extremely easily and exactly executed by this method, by which the sintering operation is stabilized and the cost of the operation is greatly reduced.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides efficient sintering by appropriately controlling the raw material heat level when sintering raw materials such as ore using a Dwight Lloyd sintering machine. It is related to a method that makes it possible.

<Prior art and its problems> Currently, the agglomeration of raw materials used in blast furnaces, etc. is generally carried out using a Dwight Lloyd type sintering machine, and the somesintering process is as shown in Figure 2.

That is, in FIG. 2, the sintering compound raw materials 3 charged from the hopper 2 to the raw material feeding section of the sintering machine 1 are ignited from the surface in the ignition furnace 4, and are arranged in parallel along the moving direction of the raw material storage pallets. The combustion zone is sucked downward by the provided exhaust fan 5. In other words, the sintering reaction progresses toward the lower layer of the charged material due to the downward ventilation from the exhaust fan 5, and sintering is completed in the entire height direction in the ore discharge section, resulting in a sintered cake. It is formed. At this time, there is usually a high temperature red zone 6 in the lower layer of the sintered cake, which is usually discharged before being cooled.

In this case, the return generation rate, coke consumption rate,
The electric power consumption and other factors differ greatly, and therefore, controlling the heat level during sintering work has been an extremely important issue.

However, in reality, it is extremely difficult to grasp the firing temperature state of the sintering compound raw materials, making it extremely difficult to control the heat level, and it is currently difficult to stably maintain the sintering operation under suitable conditions. Met.

However, several attempts have been made to accurately understand the temperature distribution state of compounded raw materials during sintering using infrared cameras and image analysis devices. In order to
The cross-section of the sintered cake is continuously photographed in the ore discharge section of the sintering machine to create a color pattern of the temperature condition in the width direction of the pallet, and based on this, the amount of raw material supplied in the width direction, the raw material density, and the thickness of the raw material layer are controlled. (Japanese Patent Publication No. 57-51453).

(bl In order to understand and manage the pallet wear situation, the cross-section of the sintered cake is photographed for each pallet in the ore discharge section of the sintering machine, and based on this, the area ratio of the red tropical area (ratio to the total cross-sectional area) is calculated. A method in which it is determined that the end face of the pallet is worn out if the area ratio is greater than or equal to a predetermined value after analyzing the area ratio, and the pallet end face is determined to be worn out, and the method is then dealt with (Japanese Unexamined Patent Publication No. 61-133327).

(In order to control the quality of C1 sintered ore, the boundary of the red-hot layer that appears on the upper surface of the raw material head is photographed. The cross-section of the sintered cake installed at the ore discharge section is photographed to determine the red-hot layer thickness in the cross-section of the sintered cake. Based on the data from the camera and wind box thermometer, the average heat front velocity (average moving speed of the front boundary of the red-hot layer), average heat-behind velocity (average moving speed of the rear boundary of the red-hot layer), and average high temperature retention time are calculated. Method for estimating the state of the red-hot layer by calculating
66685).

etc. have been proposed.

However, with the above method (al), there is a problem in that it is difficult to grasp the overall temperature distribution trend in the width direction, as it is normal for the firing conditions to vary widely from pallet to pallet. Regarding method b), there is a problem that the firing balance often changes in the longitudinal direction of the sintering machine, and the obtained data does not necessarily apply to another specific pallet. Both methods have the problem that the red zone thickness varies greatly for each pallet, making it impossible to fully grasp the red zone thickness of a particular pallet. This could not be used as a means to obtain data for proper control.

In other words, the cross section of the sintered cake at the ore discharge section of the sintering machine is
Since the temperature distribution varies from pallet to pallet and has large variations, it is not possible to accurately grasp the overall heat level of the raw materials for sintering by relying on the temperature distribution of the cross section. It was impractical to perform appropriate heat level control based on data.

<Means for Solving the Problems> From the above-mentioned viewpoint, the present inventors accurately detected the heat level of the sintered compound raw material without being affected by the reaction variation of individual bullets, and based on the data. As a result of intensive research to provide a means for appropriately controlling the heat level, the following findings 8) to C) were obtained.

A) In sintering work using a normal Dwight Lloyd sintering machine, the cross section of the sintered cake is exposed perpendicular to the direction of progress during ore discharge, as shown in Figure 3. , Red Tropical 6 still exists in the lower layer of this cross section,
Using an infrared camera and a general image processing device, it is possible to easily detect whether or not there is a high temperature area above a certain temperature in the red tropics (numeral 7 in FIG. 3 indicates a pallet). .

B) Even without analyzing the temperature distribution of the cross section in detail, it is possible to focus only on the presence or absence of a high-temperature red zone with a temperature higher than a specific temperature, and to determine whether the cross-section of the sintered cake discharged from the pallet has a high temperature higher than the specific temperature. Examining the relationship between the frequency of red tropical occurrence, return ore generation rate, and operational data showing heat levels such as waste heat recovery steam volume, etc.
An extremely strong correlation is observed between the two.

Figure 4 investigates the relationship between the frequency of occurrence of this high-temperature red tropical zone, the "return generation rate" and "exhaust heat recovery steam generation amount" that are indicators of heat level, and the cold strength of the sintered cake. As a result, Figure 4 shows the following. In other words, when high-temperature red heat is no longer observed in the sintered cake in the ore discharge area, the return generation rate increases (yield decreases), and the amount of waste heat recovery steam decreases and the strength of the sintered cake decreases. .

Therefore, in this case, it is necessary to increase the heat level of the blended raw materials by increasing the coke blending ratio.

On the other hand, when the frequency of occurrence of high-temperature red tropics exceeds a certain level, the improvement range of specifications becomes smaller, and if the frequency of occurrence of high-temperature red tropics becomes too high, it means that the coke consumption rate increases more than necessary. ing. Therefore, in this case, it is necessary to lower the coke blending ratio to the blended raw materials to return to an appropriate heat level.

C) Therefore, it is determined whether or not there is a high temperature red zone higher than a predetermined temperature obtained from experiments and actual results in the cross section of the sintered cake discharged from each pallet, and this is determined for a certain unit time (
If you investigate several defects in the sintering machine over a period of time that allows you to observe them, you can accurately determine the heat level of the sintering compound raw materials based on the frequency with which the high-temperature red hot spots appear, without being greatly affected by variations from pallet to pallet. By adjusting the coke blending ratio based on this, it is possible to stably control the heat level of the blended raw materials within a sufficiently appropriate range.

The present invention has been made based on the above knowledge, and is based on the following: ``As schematically shown in Fig. 1, the cross section of the sintered cake that is continuously fired and moved is taken at the sintering machine discharge section. The image is photographed by an infrared camera 8, and the image is analyzed by an image analyzer 9 to measure the frequency at which high-temperature red zones with a temperature higher than a predetermined temperature appear within a unit time, and based on the measurement results, the coke composition of the sintering raw material is determined. It is characterized by the fact that the heat level of the sintering raw material can be adequately controlled by adjusting the rate.

Here, the time for measuring the frequency of occurrence of high-temperature red zones above a predetermined temperature may be long enough to eliminate the influence of reaction variations due to individual pallets, but it is preferable to It is best to choose a time during which the cross section of the ore can be observed. In other words, by investigating the rotation of the sintering machine, it is possible to almost completely eliminate noise caused by variations from one machine to another.

Further, the temperature range of the red tropics in which the frequency of appearance should be counted may be determined by taking into consideration the type of ore raw material, the characteristics of the sintering machine, etc., and the lower limit of the above temperature is set based on preliminary experiments, actual results, etc.

Next, the present invention will be explained by examples.

<Example> First, as an example of the present invention, when iron ore charged in a blast furnace is sintered in a Dwight Lloyd type sintering machine, an infrared camera is placed in the ore discharge section of the sintering machine as schematically shown in Fig. 1. By continuously photographing the cross section of the sintered cake that is discharged and analyzing the images with an image analysis device, we can measure the frequency of occurrence of red tropics over 900℃ and the amount of time it takes to observe the entire pallet. did.

Subsequent sintering operations were carried out by adjusting the amount of coke blended so that the frequency of occurrence of this high-temperature red zone was 20 times.

Note that the above-mentioned "temperature" and "set number of high-temperature red tropical appearance frequencies at the temperature" are values that yielded good results in preliminary experiments.

=9- On the other hand, as a comparative example, we conducted a sintering process using the same sintering machine using the same raw materials using a conventional method that does not rely on image analysis of the cross section of the discharged ore sintered cake as described above. carried out.

The results of these sintering operations are compared and shown in Table 1.

Table 1 As is clear from the results shown in Table 1 above, according to the operation of the present invention example using the high-temperature red tropic appearance frequency as an operation guide, the return generation rate was 0.0% compared to the previous operation. 5% reduction, coke consumption rate 0.2kg/l,
It can also be seen that the electric power consumption rate is reduced to 0.2 H/l.

In addition, Figures 5 and 6 show the relationship between the frequency of occurrence of high-temperature red tropics, return ore ratio (%), and steam recovery amount (T/H) under the above conditions, which was investigated for reference. This is the result.

<Summary of Effects> As explained above, according to the present invention, it is possible to carry out appropriate control of the heat level in the sintering compound raw materials extremely easily and accurately, stabilizing the sintering work and significantly reducing operating costs. This brings about extremely useful effects in industry, such as making it possible.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram illustrating the implementation status of the present invention. FIG. 2 is a conceptual diagram illustrating a sintering process using a Dwight Lloyd sintering machine. FIG. 3 is a schematic diagram illustrating a cross section of a sintered cake appearing in an ore discharge section. FIG. 4 is a graph showing the general trends of the return ore generation rate, the amount of waste heat recovery steam generation, and the cold strength of the sintered cake with respect to the frequency of occurrence of high-temperature red tropics. FIG. 5 is a graph showing the relationship between the frequency of appearance of high-temperature red tropics and the return ore ratio obtained in the test in the example. FIG. 6 is a graph showing the relationship between the frequency of high-temperature red tropical appearance and the amount of steam recovery obtained in the test in the example. In the drawings: 1...Sintering machine, 2...Hopper. 3... Sintering compound raw material, 4... Ignition furnace. 5...Exhaust fan, 6...Red tropics. 7...Palette, 8...Infrared camera. 9... Image processing device.

Claims (1)

[Claims] The cross section of the sintered cake that is continuously fired and moved is photographed with an infrared camera at the sintering machine discharge section, and the image is analyzed by an image analysis device to generate a high temperature above a predetermined temperature within a unit time. A method for controlling the heat level of a sintered ore raw material, the method comprising measuring the frequency at which red hot spots appear and adjusting the coke blending ratio of the sintered raw material based on the measurement results.