JPS6157364B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a blast furnace in which coke and iron sources such as sintered ore and pellets (hereinafter referred to as ore) are charged in layers from the top of the furnace. The present invention relates to a method for distinguishing between coke and ore by detecting a difference, and for distinguishing each layer.

Generally, in a blast furnace, a fixed amount of coke as a heat source and reducing agent and ore as a source of iron to be reduced are charged in layers. This aims to reduce the ventilation resistance when the reducing gas generated in the lower part of the blast furnace (hereinafter referred to as the furnace gas) rises inside the furnace, and to improve the contact between the charge and the furnace gas. It is something. However, the coke and ore charged into the furnace have different particle sizes, so their ventilation resistance characteristics are significantly different, and the flow of gas in the furnace is greatly influenced by the thickness of the deposited layers of coke and ore. Disturbances in the gas flow within the furnace lead to abnormalities in the descent of the charge such as shelves and slips, making blast furnace operation unstable. Therefore, in order to maintain stable operation, it is necessary to always adjust the layer thickness distribution of the charge so as to obtain a desired gas flow distribution. The layer thickness distribution can be adjusted, for example, by changing the position of the armor plate, but for this purpose it is necessary to reliably measure the deposited layer thickness of the charge charged into the furnace.

FIGS. 1 and 2 show a sonde for measuring charge layer thickness according to the present invention. These sondes 7, 7' penetrate the furnace wall 4 of the blast furnace and are inserted into the furnace.
The coke layer and ore layer are detected by utilizing the fact that there is a large difference in electrical resistance between coke 5 and ore 6 charged into the furnace. That is, while the electric resistance value of coke 5 at room temperature is 1 to 3 Ω, that of ore 6 is 5000 to 1000 Ω. To measure the charge deposit layer thickness, two sondes 7 and 7' having a pair of electrodes 10 and 11 with an insulating material 12 in between are inserted and fixed into the furnace from the furnace wall 4 with a height h apart. From the changes in the electrical resistance of the charge measured with sondes 7 and 7', it was determined that the coke layer or
This is done by determining whether it is an ore layer. This principle is shown in FIG. In this figure, the solid line represents the measurement results of the upper sonde 7, and the dotted line represents the measurement results of the lower sonde 7'. That is, by determining the time θ for the boundary A between the coke layer and the ore layer detected by the upper sonde 7 (determined by a sudden change in resistance value) to fall to the level of the lower sonde 7', the equipment can be determined. Determine the falling object descending speed V (V=h/θ). On the other hand, the layer thickness l _pre (or l _cpke ) can be calculated from the passage time t _pre (or t _cpke ) of the ore layer (or coke layer) detected by the upper sonde 7 or the lower sonde 7' as l _pre = V x t _pre (or l _cpke = V x t _cpke ).

Therefore, in this method, it is important to reliably determine whether it is a coke layer or an ore layer from the electrical resistance values detected by the sondes 7, 7'. However, in the results of measuring electrical resistance in an actual furnace, as shown in Figure 4, which shows an example of a measurement chart, the electrical resistance value changes significantly, and does not indicate the specific resistance values of coke or ore, but simply the magnitude of the electrical resistance value. There is a problem in that it is difficult to determine whether it is a coke layer or an ore layer based only on the level difference. That is, in the coke layer, the electrical resistance value hunts between a low level of 2 to 3 Ω and a very high level of 1000 Ω or more, and in the ore layer, it changes stepwise in the range from 20 to 1000 Ω. These are caused by the following reasons. In other words, blast furnaces usually use coke with a particle size of 30 to 80 mm and ore with a particle size of 5 to 20 mm, but in the case of a coke layer, the particle size is large, so the voids in the deposited layer are large, and the coke layer is large. Since the surface is rough compared to the surface of the ore, the contact of the sonde 7 or 7' with the electrode 10 or 11 becomes unstable, which causes the electrical resistance measurement circuit to be interrupted.
Along with this, the electrical resistance value changes from 2 to 3 Ω (when the coke and electrode are in contact).
and 1000Ω or more (when the coke and electrode are separated). On the other hand, in the ore layer, the surface is relatively smooth and the particle size is small, so the electrode 10,
Since there are many contact points with 11 and the measurement circuit is not interrupted, the resistance value is stable at a level specific to the ore. In addition, the reason for the step-like change is that iron oxide, which is the main component of sintered ore, pellets, etc., has the characteristic that the electrical resistance value decreases significantly as the temperature rises, so probe 7 or 7' is inserted. This is because the temperature of the ore changes in accordance with the change in the furnace temperature at the same level, so the electrical resistance value also changes. Therefore, the fourth
The measurement example shown in the figure shows that the temperature of the ore changes for each ore layer.

The present invention automatically determines whether it is a coke layer or an ore layer by using fluctuations in the electrical resistance measurement signal (hereinafter referred to as measurement signal), and calculates the transit times t _pre and t _cpke of each deposited layer. calculate.

The method of the present invention utilizes the fact that, as can be seen from the measurement signal example shown in FIG. 4, the patterns of disturbances in the measurement signal in the coke layer and disturbances in the measurement signal in the ore layer are different. In other words, in the coke layer, the electrical resistance changes from a low level to a high level in a short time, whereas in the ore layer, this signal change range is small and does not fluctuate very much. The change is divided into two levels, and it is determined whether the measurement signal changes between each level within a certain unit time, and if there is a change, the coke layer,
This is a signal processing method that utilizes outputting a case where there is no change between either one or two levels as an ore layer.

FIG. 5 is a block diagram showing an embodiment of the present invention, and FIG. 6 is a time chart illustrating the operating status of each device. To explain the present invention using the block diagram of FIG.
and 17 in parallel. The comparator 16 is connected to a setting device 14 that sets a high level (H level) within a range of 60 to 80% of the maximum hunting width of the measurement signal, and the comparator 17 is connected to a setting device 14 that sets a high level (H level) within a range of 20 to 40% of the maximum hunting width of the measurement signal. The lower level (L
It is connected to a setting device 15 that sets the level). Comparator 16 is flip-flop circuit 1
9 (D-FF with smoothing circuit), AND gate circuit 2
1. The comparator 17 is connected to the arithmetic circuit 26 via a coke counter 23, while the comparator 17 is connected to the arithmetic circuit 26 via a flip-flop circuit (D-FF with smoothing circuit), a NAND gate circuit 22, and an ore counter 24. A clock pulse generator 18 is connected between the flip-flop circuits 19 and 20.
The flip-flop circuit 19 and the NAND gate circuit 22 are connected to each other, and the flip-flop circuit 20 and the AND gate circuit 21 are connected to each other. Further, a clock pulse generator 25 is provided between the coke counter 23 and the ore counter 24, so as to output a reset signal from the ore counter 24 to the coke counter 23 and from the coke counter 23 to the ore counter 24, respectively. Further, the coke counter 23 and the ore counter 24 are configured to output data to an arithmetic circuit 26, respectively.

The measurement signals from sondes 7 and 7' are transmitted to amplifier 13.
After being amplified here, the signal is processed by the circuit according to the present invention configured as described above. It is determined as follows whether a coke layer or an ore layer is being detected. Sonde 7 below
The signal processing when processing the measurement signal from. The measurement signal is amplified by the amplifier 13, the output from which is input in parallel to comparators 16 and 17, and the measurement signal input to the comparator 16 is input from the setting device 14, which is a high level value (H level) to be described later. The measured signal is compared with the H level, and is output to the flip-flop circuit 19 only when the measured signal is higher than the H level. Flip-flop circuit 19
has a function of keeping the signal at the "1" level for that time if a signal is input from the comparator 16 between the time when the clock pulse generator 18 sent the previous pulse and the time when the current pulse is sent. Therefore, if there is an input from the comparator 16 to the flip-flop circuit 19 within the above-mentioned time, "1" is sent from there to the AND gate circuit 21.
A signal is output, and at the same time the NAND gate circuit 22
A signal of “1” is also output.

On the other hand, the measurement signal input to the comparator 17 is compared with a low level (L level) to be described later, and is output to the flip-flop circuit 20 only when this signal is lower than the L level. This flip-flop circuit 20 is a clock pulse generator 1.
If an input is received from the comparator 17 between the time when the previous pulse was sent from 8 and the time when the current pulse is sent, the signal is held at the level of "1A" for this time and is ANDed with the NAND gate circuit 22. Output to the gate circuit 21. The clock pulse oscillator 18 outputs 0.5~
Since a clock pulse is transmitted at a fixed period of 10 seconds, if the measurement signal input to the amplifier 13 is a signal that detects a coke layer, the AND gate circuit 21 indicates that a signal of H level or higher is detected. A signal of ``1'' and a signal of ``1A'' indicating that a signal below the L level is detected are input at the same time, and an H level signal indicating that a coke layer has been detected is outputted from there to the coke counter 23. Similarly, the “1” and “1A” signals are simultaneously input to the NAND gate circuit 22, but from here the ore counter 2
No H level signal is output to 4. The same processing as described above is performed when a signal detecting an ore layer is input to the amplifier 13, and in this case, it is not output from the AND gate circuit 21 but is output from the NAND gate circuit 22.
An L level signal will be output only from.
Note that this will be described further later.

When signals are input to the coke counter 23 and the ore counter 24, the respective times are integrated based on the clock pulses obtained from the clock pulse generator 25, and the integrated values are output to the arithmetic circuit 26. If there is an input to the coke counter 23, the ore counter 24 is reset by the signal, and if there is an input to the ore counter 24, the coke counter 23 is reset, so the coke counter and the ore counter can accumulate at the same time. It will never be done.

Although the above description describes the processing of the measurement signal by one sonde, the processing of the signals from a plurality of sondes can be carried out by processing them separately or by providing two series of the processing circuits. The above process can be performed for multiple sondes. In addition, the clock pulse oscillator 18
The period of the clock pulse sent from is 0.5 to 10
It is effective to set the time within seconds; measurement accuracy will decrease if the time is less than 0.5 seconds or more than 10 seconds.

Note that the arithmetic circuit 26 calculates the coke layer passage time t _cpke from the coke counter 23 and the ore counter 2.
Since the ore layer passage time t _pre from 4 is input and the distance h between the sondes 7 and 7' is fixed, the descending speed V of the charge is determined by the coke layer and ore detected by the upper sonde 7. From the time θ for the layer boundary A to descend to the level of the lower sonde 7', it can be found as V=h/θ, and from the coke layer passage time t _cpke and the descending velocity V of the charge, the coke layer thickness l _cpke is , l _cpke = V x t _cpke , and the ore layer thickness l _pre can be calculated as l _pre = V x t _pre .
In addition, in the present invention, a high level (H level)
The value of is set between 60 and 80% of the hunting width of the measurement signal, and the value of the low level (L level) is set between 20 and 40% of the hunting width of the measurement signal.

Next, the operating status of each device according to the present invention will be explained based on FIG. 6. In the initial state between 0 and A, the measurement signal is output from the amplifier 13 as a signal below the L level, so there is an output from the comparator 17, and a signal of "1A" is output from the flip-flop circuit 20 to the NAND gate circuit 22. has been done. Since there is no output from the comparator 16, there is no output from the AND gate circuit 21, and since there is an L level output only from the NAND gate circuit 22, this state is regarded as an ore layer and the ore counter 24 is operated. When the measurement signal starts hunting at point A, the measurement signal changes across the H level and L level, so there are outputs from both comparators 16 and 17, and therefore the AND gate circuit 2
There is an output from 1, but there is no output from the NAND gate circuit. From this point, it is assumed that the coke layer has changed, and the coke counter 23 starts operating, and at the same time, the ore counter 24 stops, outputs the integrated value to the arithmetic circuit 26, and is reset. B
At point, the measurement signal changes slightly near the L level, so the comparator 17 outputs and the flip-flop circuit 20 outputs "1A". However, since no signal exceeding the H level is input, the flip-flop circuit 19 does not output an output of "1 A". From this point, the coke counter 23 is regarded as an ore layer, and the coke counter 23 is stopped, and after outputting the accumulated value up to now to the arithmetic circuit 26, it is reset, and only the ore counter 24 performs the accumulation. At point C, the measurement signal is between H level and L level, so there is no output from both comparators 16 and 17, so the output is only from the NAND gate circuit 22, and the ore layer is regarded as a continuous ore layer from point B. Only counter 24 continues to operate. At point D, the conditions are the same as at point A, and between E and F, the conditions are the same as at point C.
-D under the same conditions, and at point F, above point B and H, L
Although the levels are reversed, the conditions are the same and it is judged as an ore layer.

As described above, according to the present invention, when a coke layer and ore layer in a blast furnace are detected by a sonde that uses electrical resistance, it is determined whether the layer is a coke layer or an ore layer based on the difference in the hunting pattern of the measurement signal. Therefore, even if the electrical resistance value of the ore changes due to the temperature change of the ore in the furnace, the coke layer and the ore layer can be accurately determined. This has the effect that the layer thickness can be measured with high precision.

[Brief explanation of the drawing]

Fig. 1 is a sectional view illustrating a sonde installed in blast furnaces according to the present invention, Fig. 2 A is an enlarged sectional view of the main part illustrating the structure of the sonde, and Fig. 2 B is A of Fig. 1 A. -A' cross-sectional view, Figure 3 is a schematic diagram explaining the principle of the method of the present invention, Figure 4 is a waveform diagram showing an example of a signal measured by a sonde in an actual reactor, and Figure 5 is an embodiment of the present invention. The block diagram and FIG. 6 are time charts showing the operating status of each device according to the present invention. 4: furnace wall, 5: coke layer, 6: ore layer, 7,
7': Sonde, 10, 11: Electrode, 12: Insulator, 13: Amplifier, 16, 17: Comparator,
18, 25: Clock pulse generator, 19, 2
0: Flip-flop circuit, 21: AND gate circuit, 22: NAND gate circuit, 23: Coke counter, 24: Ore counter, 26: Arithmetic circuit.

Claims (1)

[Claims] 1. Output the measurement signal of the electric resistance value of the charge from the sondes for detecting the charge layer in the blast furnace inserted at different heights, and
A high comparison level is set between 80% and a low comparison level is set between 20% and 40% of the maximum hunting width, and a clock pulse is generated at a period set between 0.5 and 10 seconds to perform measurements using the sonde. The blast furnace interior is characterized in that the signal is compared with the high comparison level and the low comparison level each time the pulse is generated, and when both the high level and the low level are detected, it is determined that the coke layer is determined, and other cases are determined to be the ore layer. How to distinguish layers.