JPH0565089B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for measuring hot metal temperature.

More specifically, the present invention relates to a hot metal temperature measuring method that can automatically correct measurement errors due to slag when measuring the hot metal temperature with a radiation thermometer.

(Conventional technology) Hot metal that leaves the blast furnace passes through a hot metal trough, where slag is first removed by a skimmer, and then through a tilting trough, it is poured into a hot metal transport vehicle such as a torpedo car, and then transported to a predetermined location for treatment in the next process. transported to. On this occasion,
The temperature of the hot metal is measured after removing the slag with a skimmer.

The temperature of hot metal during tapping in a blast furnace is one of the important factors for estimating the condition inside the furnace, but accurate measurement is difficult because slag coexists.

Figure 1 shows a typical example of the principle of hot metal temperature measurement using a conventional radiation thermometer.

That is, when measuring the temperature of hot metal 12 in the blast furnace tap trough 10 using the radiation thermometer 14, the output signal of the radiation thermometer 14 is sent to the radiation thermometer converter 20 to display the temperature. In that case, since the thermometer 14 is calibrated in accordance with the temperature of a black body (emissivity=1), the correction value is set in accordance with the emissivity of the hot metal. The emissivity of hot metal changes somewhat depending on its temperature. However, when the slag 16 floats on the hot metal, the radiation thermometer indicates an apparently higher temperature because the emissivity of the slag is higher than that of the hot metal. Also, if cooled slag floats, it may indicate a low temperature.

Since the purpose is to measure the temperature of hot metal, abnormal temperature indications from slag should be considered noise.

By the way, the conventional radiation thermometer converter 20 is a simple processing device, and as shown in the figure, it has functions such as emissivity correction value setting, peak value detection, and averaging (average temperature). However, in the conventional radiation thermometer, the function of the converter shown in FIG. 1 is not fully activated due to the floating flow of slag. That is, (1) Emissivity correction value setting function Since the set value is fixed and does not have a function to distinguish between hot metal and slag, it may indicate an incorrect temperature.

(2) Peak value detection function The peak value is unreliable because the temperature indication is fluctuated by slag.

(3) Averaging function The average temperature during a certain time period is also unreliable due to fluctuations in the temperature indication due to slag.

For example, in the conventional method, the emissivity correction value is fixed, so if the temperature of hot metal is about 1500℃, the correction value is
Set it to about 0.40 to 0.45. When the slag floats there, the emissivity of the slag is about 0.70 to 0.75, so
The temperature will be measured as approximately 60°C higher. At this time, what is needed is the temperature of the hot metal, so the large amount of slag that flows out causes fluctuations in temperature, making it difficult to measure the peak value and average temperature. Removal of slag by the skinmer is not necessarily complete, and flow of slag is unavoidable, and errors in measured temperatures due to this are also unavoidable.

(Problems to be Solved by the Invention) Thus, one object of the present invention is to provide an accurate and inexpensive method of measuring hot metal temperature that substantially eliminates the influence of slag.

Another object of the present invention is to provide a method that enables accurate grasping of blast furnace conditions and stable operation by measuring accurate hot metal temperature.

(Means for solving the problem) As already mentioned, it is inevitable that hot metal flows mixed with slag, and this is the cause of problems in measuring hot metal temperature using conventional radiation thermometers. It was hot. Therefore, it would be possible to solve this problem by using identification methods other than radiation thermometer data, such as pattern recognition, but this would require adding expensive sensors and processing equipment.

After further investigation, we learned that by treating temperature measurement errors caused by slag as disturbances in the measurement data, it is possible to automatically correct temperature measurement errors, making it extremely easy to accurately measure temperature. Completed the invention.

That is, the present inventor has proposed a method for measuring the temperature of hot metal flowing through a blast furnace tap pipe using a radiation thermometer.
To accurately measure the hot metal temperature by automatically correcting measurement errors caused by the slag by distinguishing between the hot metal and the slag in the measurement data when there is slag with a different emissivity from the hot metal on the surface of the hot metal. We have discovered that it can be characterized by

Here, the present invention provides a method for measuring the temperature of hot metal flowing through a blast furnace tap pipe with a radiation thermometer, in which continuously measured data is recorded, calculations are performed at predetermined intervals, and the average value and standard deviation are determined. Compare the standard deviation with a preset threshold, and if the standard deviation is larger than the threshold, hold the previous output value,
On the other hand, if the standard deviation is smaller than the threshold, then the average value is compared with a preset temperature threshold, and if the average value is smaller than that, it is output as is; If the average value is large, the emissivity of the slag is corrected and the temperature is corrected before being outputted.The measurement error due to the slag is automatically corrected and the hot metal temperature is accurately measured. This is a unique method for measuring hot metal temperature.

That is, according to the present invention, as an automatic correction means for the measurement error, the standard deviation and average value are sorted by a certain threshold value. For example, when the standard deviation becomes too large, the previous data ( On the other hand, if the average value exceeds a certain threshold value, the emissivity of the slag is changed to correct the measured value. All of these operations can be performed by computer calculations.

In this way, the present invention merely adds a relatively inexpensive processing device (mainly a microcomputer) called a hot metal temperature correction device to the radiation thermometer converter to the conventional device, and the temperature can only be recorded by the radiation thermometer. This is a method of processing using

(Function) Here, an example of temperature recording by the conventional method before processing by the method according to the present invention is shown graphically in FIG.

As is clear from the illustrated graph, the measured temperature rises after the start of tapping from the blast furnace, but initially
The temperature remains relatively stable for about 100 minutes, but
As more slag flows out, the measured temperature begins to fluctuate significantly. However, after a certain period of time,
For example, after 180 minutes, no slag is seen flowing out, and the measured temperature becomes stable again. The maximum measured temperature difference at this time is said to be as much as 61 degrees Celsius.

Here, according to the present invention, the output fluctuation after 100 minutes in the figure is automatically corrected. A microcomputer is used for the hot metal temperature correction device. The input signal processing (arithmetic processing) in that case will be explained in detail with reference to FIG.

That is, first, the standard deviation (σ) of the measurement data
is calculated, and then its standard deviation (σ)
Compare with a certain threshold (B). If the standard deviation (σ) is too large, the previous output value is used as the output value, while if the standard deviation is within a certain range, then the average value () of the measured data is used.
is compared with H, which is also a threshold value. At this time, if the average value () is small enough, it is used as the output value, and if it is larger than that, the emissivity (ε) of the slag for the thermometer etc. is corrected, and the output temperature is automatically corrected. conduct.

The method of the present invention has great practical advantages, such as the automatic correction device being relatively inexpensive and the accurate temperature of the hot metal being known in real time.

(Example) The present invention was implemented using a configuration similar to that shown in FIG.

Temperature measurement according to the present invention was carried out according to FIG.

Radiation thermometer of the present invention and conventional thermocouple (consumable type)
The temperature of the same hot metal was measured simultaneously at the same point in the blast furnace tap runner.

The results are summarized in Figure 4.

The indicated value is within ±10°C of the average value. Assuming that the thermocouple value is correct, the radiation thermometer reading is 15°C lower on average because the emissivity ε = 0.45. ε=0.45 was used as the past average value.

In addition, in this example, B=0.9, H=1550°C
And so. The sampling period was 50 msec, the sampling time was at 3 second intervals, and the calculation period was 60 seconds.

(Effects of the invention) As detailed above, when measuring the temperature of hot metal with a radiation thermometer, the temperature of hot metal may be about 60°C higher using the conventional method, but the method of the present invention has an error of ±10°C. Can measure accurately within a range.

Also, for example, the thermocouple used in the above example is
It is an expensive Pt-Pt (90) + Rh (10) type, and if it is immersed in hot metal, it will become unusable after a few experiments even if a protective tube is used, making it unusable. However, according to the present invention, it is possible to measure temperature with high accuracy through simple data processing, which has great practical significance.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of a conventional measurement method using a radiation thermometer; Fig. 2 is a graph illustrating a temperature measurement record by the conventional method after the start of tapping; Fig. 3 is a graph showing the temperature of hot metal according to the present invention. A schematic illustration of the principle of the correction method;
and FIG. 4 is a graph showing data of an example in which hot metal at the same location was simultaneously measured using a radiation thermometer and a consumable thermocouple used in the method according to the present invention. 10: Tapping trough, 12: Hot metal, 14: Radiation thermometer, 16: Slag.

Claims (1)

[Claims] 1 In the method of measuring the temperature of hot metal flowing through the blast furnace tap trough using a radiation thermometer, the continuously measured data is recorded, calculations are performed at a predetermined period to determine the average value and standard deviation, and the standard deviation and preset value are calculated. If the standard deviation is larger than the threshold value, the previous output value is held; on the other hand, if the standard deviation is smaller than the threshold value, then the average value and the preset value are compared. Compare it with the temperature threshold value, and if the average value is smaller than that, output it as is,
On the other hand, if the average value is larger than that, the emissivity of the slag is corrected, the temperature is corrected, and then output. A method for measuring hot metal temperature.