JP3379386B2 - Refractory wear evaluation method and apparatus, and refractory management method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the degree of wear of a refractory material lined inside the iron shell of an industrial furnace such as a blast furnace and a converter, an apparatus used for carrying out the method, and the same. The present invention relates to a refractory management method and an apparatus used for implementing the method.

[0002]

2. Description of the Related Art Usually, refractory bricks are lined inside the iron shell of a blast furnace. Since the refractory bricks at the bottom of the blast furnace are constantly exposed to hot metal, they gradually wear out as the blast furnace operates. For example, the thickness of a refractory material that was 2,000 mm or more at the time of burning may decrease to about 300 mm at the time of blowing off after a dozen years. Accurately estimating the life expectancy of a blast furnace by accurately measuring the transition of the remaining thickness of refractory during blast furnace operation is
It is very important to prevent serious accidents such as melting of iron skin due to hot metal and outflow of hot metal, and effective use of blast furnace assets.

For this reason, many methods for measuring the remaining thickness of refractory bricks have been conventionally proposed. For example, in Japanese Patent Laid-Open No. 49-50961, a sinusoidal excitation force with an audible frequency is applied to a measured brick for an industrial furnace, its mechanical impedance is measured, and the outside of the furnace is measured based on the peak value of the mechanical impedance. Discloses a method of non-destructively measuring a brick thickness.

Further, Japanese Unexamined Patent Publication No. 58-27002 discloses a stamp which is an indeterminate refractory in which an opening is formed in a part of the iron shell and a metal rod is buried in the refractory material or between the iron shell and the refractory material. By directly connecting to the material and hitting one end of the metal rod, an elastic wave is efficiently generated in the refractory, and the time required for the elastic wave to make a round trip in the refractory is measured, and the round trip time and elasticity in the refractory are measured. A method of measuring the thickness of the refractory material from the wave propagation velocity has been proposed. Further, in JP-A-62-297710, the surface of the iron shell of the blast furnace is struck with a hammer, the elastic waves generated by this impact propagate through the refractory, causing reflection on the core side surface,
A method is disclosed in which the round-trip time of returning to the surface of the iron skin is measured again, and the thickness of the refractory brick is measured from the propagation speed of the elastic wave in the refractory and the round-trip time which are obtained in advance. Here, when the elastic wave reflected inside the refractory is received, the receiving sensor selectively receives a predetermined frequency from the elastic wave having a frequency of several kHz to several 100 kHz, and superimposes the waveforms on the embrittlement portion. , It is proposed to measure the thickness of each part such as the solidification part. These two methods have the advantage that the processing contents for measuring the thickness of the refractory brick from the measurement data are simple and can be measured at any place.

The most popular method in recent years is to embed a thermometer inside a brick and measure the heat flux transmitted from the core side to the iron shell side. In this method, around 100 thermometers were embedded in the bricks along the entire circumference of the side wall of the blast furnace, and after measuring the heat flux, the position where the heat source at the pig iron solidification temperature of 1150 ° C was calculated from the heat conduction equation. Then, it is a method of estimating the remaining thickness of the brick.

According to Japanese Patent Laid-Open No. 63-297512, when an output of the embedded thermometer indicates an abnormally high temperature, an impact elastic wave sensor is placed at the position where the thermometer is embedded. Disclosed is a method of forming a protective layer on the inner surface of a refractory material by moving the sensor to a corresponding surface position, measuring the remaining thickness while running the sensor, and further performing an erosion suppression operation on the blast furnace bottom refractory material based on the measurement result. Has been done.

[0007]

First, in the method disclosed in Japanese Patent Laid-Open No. 58-27002, a steel bar at a measurement point is opened and a metal rod in contact with a brick is struck. There is a problem that the measurement reproducibility is poor depending on the contact state and the hit state. In addition, a method of propagating elastic waves (elastic shock waves, ultrasonic waves) from the surface of the brick on the iron skin side toward the core side (Japanese Patent Application Laid-Open No. 2006-242242).
49-50961, JP-A-58-27002, JP-A-62-297710,
Japanese Patent Laid-Open No. 63-297512) discloses that most of the elastic wave energy is reflected at cracks and embrittlement portions (where many cracks are present due to embrittlement of a refractory material) inside the brick, and its propagation is Since it is blocked, there is a drawback in that it is not possible to obtain information on the cracked portion, the embrittled portion on the core side, and the solidified layer which is a mixed layer of the refractory into which the hot metal has penetrated and the solidified pig. However, it is needless to say that the thickness of the sound part (the part where there is no crack or embrittlement and the physical property value is close to the value at the time of blast furnace construction) is required for the management of refractory bricks. It is also important to measure the thickness of the solidified layer and the solidified layer because they play a role of protecting the brick erosion due to the hot metal. Further, thermal stress applied to the refractory in the furnace may cause cracks in the sound part of the refractory. This crack is from the iron skin side of the remaining thickness of the sound part.
It has been revealed from past blast furnace dismantling surveys that it frequently occurs at 50 to 90% of the locations. When such a crack is present, there is a drawback in that even if the crack occurrence position can be measured, information on the core side cannot be obtained.

A method proposed in order to overcome this problem, which is disclosed in Japanese Patent Laid-Open No. 62-297710, is to selectively receive a predetermined frequency to measure the thickness of each portion such as an embrittled portion and a solidified portion. Has the following problems. One method of changing the degree of transmission of elastic wave energy at a discontinuous portion of elastic wave propagation characteristics such as cracks in a refractory is to change the frequency of the elastic wave, that is, the wavelength. The degree of transmission depends on the size of cracks, but generally the wavelength is from 10 to several hundreds.
It becomes larger when doubled. Since the material used as a refractory is very porous and has a large attenuation of elastic waves, it is necessary to use elastic waves having a frequency of several hundred kHz or less when the thickness of the refractory is about 1 m. Further, from the viewpoint of transmitting the crack portion, several kHz is desirable.
However, since the wavelength of the elastic wave of several kHz is about 1 m, it is about the same as the thickness of the refractory. Then, when measuring a site with a thickness of several 100 mm in a refractory with an elastic wave propagation velocity of 2000 to 4000 m / sec, the reflected waves at the boundaries on both sides are received in a combined form. Therefore, high precision measurement is very difficult.

Further, the method of measuring the heat flux by the embedded thermometer has the following problems. That is, when calculating the brick residual thickness from the heat flux, the heat transfer coefficient of the brick, stamp material, etc. is used.
Since the stamp material changes with time as it deteriorates, the difference between the heat transfer coefficient used when calculating the thickness and the actual heat transfer coefficient causes a thickness calculation error. Further, when the heat insulating layer (crack portion, embrittlement portion) is present in the brick, a part of the heat flux is blocked by this heat insulating layer, and the value of the brick thickness is calculated to be larger than the actual value. Therefore, brick management using such a thermometer is effective for constantly monitoring macroscopic brick erosion tendency using a large number of thermometers, but the measurement accuracy at each measurement point is not very high.

Further, when two or more kinds of bricks are adhered to each other to form a multi-layer structure, the elastic wave propagated from the iron skin side to the surface of the outer refractory bricks is broken at the joint portion which is the interface between the refractory bricks. Most of the energy is reflected. Therefore, the remaining thickness of the outer refractory bricks can be accurately measured, but since the reflected elastic wave that indicates the remaining thickness of the inner (core side) refractory bricks is extremely weak, the thickness can be adjusted with high accuracy. Is difficult to measure.

Further, by accurately grasping information such as whether the obtained measured value is the thickness of the sound portion or the total thickness, and whether the sound portion has cracks or cracks, it is possible to comprehensively grasp the information. It is very difficult to evaluate the degree of wear of refractories.

The present invention has been made in view of the above circumstances, and uses at least two of the thickness to the reflection source, the thickness to the embrittlement portion, and the thickness to the heat source to determine the degree of wear of the refractory. An object of the present invention is to provide a method for evaluating the wear of a refractory and a device used for carrying out the method, by which the degree of wear of the refractory can be evaluated with high accuracy and reproducibility.

Another object of the present invention is to provide a refractory management method and a device used for implementing the refractory management method, by which it is possible to easily grasp the remaining life of the refractory, the time of repair, and the location.

[0014]

According to the present invention, the thickness of the refractory material lined inside the iron shell of the furnace is measured to determine the internal state of the refractory material. A method for evaluating the degree of wear of a refractory due to a heat source in a furnace and an apparatus used for carrying out the method, wherein a first elastic wave is propagated from the outer surface of the refractory to the inner side, and a reflection source in the refractory is provided. Of the reflected wave at the first elastic wave, the thickness from the outer surface to the reflective source is calculated using the time required for the first elastic wave to make a round trip from the outer surface to the reflective source, and the first elastic wave has a lower frequency than the first elastic wave. The second elastic wave is propagated inward from the outer surface, the resonance frequency of the refractory is detected, and the thickness of the refractory from the outer surface to the embrittlement portion is calculated based on the resonance frequency. At a predetermined distance in the thickness direction near the outer surface of the Without even measure the temperature of the two positions, the temperature measurement was used to calculate the thickness from the outer surface to the heat source, with a thickness of up to a thickness and said embrittled portion of the to the reflecting source, or the and determining the wear of the refractories using thickness up thickness and the heat source to the fragile portion.

The inventions according to claims 2 and 8 include:
6 and 7, the frequency of the first elastic wave is 20 kHz or higher, and the frequency of the second elastic wave is 5 kHz or lower.

If a first elastic wave having a relatively high frequency, for example, 20 kHz or higher, of the elastic waves that can propagate in the refractory is used, the first elastic wave is cracked in the sound part of the refractory. Or, most of it is reflected here because of the high attenuation at the crack and the relatively low degree of transmission.
If no cracks or cracks are present, the embrittlement portion is greatly attenuated, and thus propagates to the boundary between the sound portion and the embrittlement portion and is reflected. Therefore, in the measurement using this relatively high frequency, it is possible to grasp the crack in the sound part, the distance to the crack part or the embrittlement part.

The frequency is relatively low, for example, 5 kHz.
The following second elastic wave has a wavelength of at least 4 times or more as compared with the above-mentioned first elastic wave of 20 kHz. Therefore, since the second elastic wave is less attenuated in a crack or the like and the degree of transmission of the elastic wave energy is large, most of the energy is transmitted to the crack, which is a discontinuous portion of the elastic wave propagation characteristic. , Cracks, and reflection at the boundary with the embrittled part, which has lower elastic wave propagation characteristics than the cracks. Therefore, in order to measure the resonance frequency, a standing wave of the second elastic wave is generated in the thickness direction of the refractory, and the frequency of this standing wave is measured to accurately measure the distance to the embrittlement of the refractory. It is possible to ask.

An air hammer, a sine wave exciter or the like can be used to generate the second elastic wave, and an acceleration clock can be used to measure the standing wave. The resonance frequency of the second elastic wave is a function of the thickness of the refractory material, but 0.5 to 3 kHz is suitable for normal measurement. In this case, if the first elastic wave is 100 kHz, the wavelength is about 1
Since it is 00 times, the degree of transmission can be significantly changed (increased).

Furthermore, the thickness from the outer surface to the heat source can be calculated by calculating the distance to the known heat source temperature from the measured temperatures and the distances in the vicinity of the outer surface of at least two locations.

At least two of the thickness to the reflection source, the thickness to the embrittlement portion, and the thickness to the heat source are used,
For example, by comparing the measured value and the difference between the measured values with a preset comparison value, the internal state of the refractory and the thickness of the refractory can be grasped with high accuracy to comprehensively evaluate the degree of wear of the refractory. It can be evaluated accurately.

The inventions as defined in claims 3 and 9 are defined in claims 1 and 2.
In 2, 6, 7, and 8, the difference between the thickness up to the reflection source and the thickness up to the embrittlement portion is obtained, and the reflection source is a crack, a crack portion, or an embrittlement portion using this difference. It is characterized by determining whether or not.

When the difference between the thickness up to the reflection source and the thickness up to the embrittlement portion is larger than a predetermined value, it can be determined that the reflection source is a crack or a crack portion other than the embrittlement portion.

The inventions according to claims 4 and 10 are claimed in claims 1 and 2.
The refractory wear evaluation method described in 2 or 3 is carried out at a plurality of locations in the furnace, and the location where L1, L2 or L3 is equal to or less than a predetermined value is detected and specified.

When the state differs depending on the position, for example, when a crack is locally generated, it is unlikely that this position will be measured in one measurement. However, the more measurement points, and the more circumferentially they are placed, the more likely it is that this location will be identified. Therefore, it is possible to carry out partial repairs and operate safely for a long period of time.

The inventions as defined in claims 5 and 11 are defined in claims 1 and 2.
Calculate the L1, L2 or L3 obtained using the refractory wear evaluation method described in 2 or 3 over time, determine the change over time of this value, and predict the subsequent change from the change over time, The feature is that the time when this predicted value falls below a predetermined value is calculated.

By setting a value that cannot be used as the predetermined value, it is possible to estimate the remaining life. In addition, it is possible to estimate the repair time by setting a value that can be continuously used by the repair as the predetermined value. In addition, the predetermined value can be set as appropriate.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to the drawings showing the embodiments thereof. Form example 1. 1 and 2 are configuration diagrams showing an apparatus for carrying out the method for evaluating the wear of a refractory material according to the present invention. A refractory brick 3, which is an object to be measured, is lined inside a steel shell 1 in a blast furnace via a stamp material 2, and the steel shell 1 and the stamp material 2 at predetermined positions are opened to form a refractory brick 3
Is exposed. In the refractory brick 3 of this opening 4,
The tip of the movable ultrasonic probe 5 is in contact with it. A contact medium 5a made of a heat-resistant resin such as urethane rubber is attached to the tip of the ultrasonic probe 5.
A gap is not formed between the tip of the and the refractory brick 3. Further, instead of attaching the contact medium 5a, the refractory brick 3 may be contacted via the contact medium. As the couplant, any substance that does not vaporize even at the surface temperature of the refractory (usually 100 to 300 ° C) and can sufficiently propagate ultrasonic waves may be used.

The ultrasonic probe 5 includes a pulsar 6 for outputting an electric signal for generating an ultrasonic wave (elastic wave), and a signal amplifier for amplifying the elastic wave detected by the ultrasonic probe 5. 7 is connected, and the signal amplified by the signal amplifier 7 is provided with an averaging processing unit 10a and a thickness measuring unit 10b,
The signal processor 10 for calculating the thickness of the sound portion is provided via the bandpass filter 8 and the A / D converter 9.

In the vicinity of the outer surface of the refractory brick 3, thermometers 11 and 11 connected to a heat flux meter 12 are embedded at predetermined intervals in the thickness direction of the refractory brick 3, and the heat flux meter 12
The signal obtained at is given to the heat conduction calculation device 13 for detecting the position of the heat source.

Further, as shown in FIG. 2, an air hammer 21 for hitting the exposed surface of the refractory brick 3 in the opening 4 is installed. A material having an appropriate hardness is selected for the tip portion 21a of the air hammer 21, and by applying a predetermined pressure with the air pressure regulator 22, an elastic wave having a predetermined frequency band of 5 kHz or less is generated. It can be propagated to the inside of the refractory brick 3. For example, when propagating an elastic wave of 0.5 to 3 kHz in consideration of the estimated value of the remaining thickness of the refractory brick 3, hard rubber is used for the tip portion 21a, and the applied air pressure can be 5 kgf / cm ^2. .

Further, on the exposed surface of the refractory brick 3 in the opening 4, an accelerometer 23 for detecting a standing wave in the brick thickness direction generated when the air hammer 21 hits the refractory brick 3.
Is attached. A signal amplifier 24 for amplifying the elastic wave signal received by the acceleration clock 23 is connected to the acceleration clock 23,
The signal amplified by the signal amplifier 24 is processed by the averaging processing unit 27a.
And a thickness measuring section 27b for calculating the thickness of a sound portion via a bandpass filter 25 and an A / D converter 26.

The data obtained by the signal processor 10, the heat source position data obtained by the heat conduction calculation device 13, and the signal processor 27
The data obtained in 1 is provided to a calculator 14 for evaluating the degree of wear, which includes a comparison calculator 14a and a wear degree evaluator 14b. The evaluation result by the computing unit 14 is given to the output device 15, and is displayed on the display, printed out, etc.
The predetermined output is made.

Next, a method for evaluating the wear of the refractory in the thus constructed apparatus will be described. Ultrasonic probe 5
Generates ultrasonic waves (transmission signal) based on the electric signal output from the pulsar 6 and transmits the ultrasonic waves to the surface of the refractory brick 3. The elastic wave propagating in the refractory brick 3 is reflected by the boundary between the sound part and the embrittlement part or the crack in the sound part. The transmission signal and the reflected signal are amplified by the signal amplifier 7, the noise component at the time of blast furnace operation is removed by the band pass filter 8, and then A / D converted by the A / D converter 9. This A /
The D-converted signal is used as an averaging processing unit 10a of the signal processor 10.
The S / N ratio is improved by adding and averaging a predetermined number of times.

The thickness measuring unit 10b is based on the equation (1)
As shown in FIG. 3, after subtracting the time t required for the ultrasonic wave to travel back and forth in the contact medium 5a from the time T required from the detection of the transmission signal to the detection of the reflection signal, it is determined in advance. Propagation velocity V of elastic wave in the fireproof brick 3
And the half of the arrival time difference are calculated to obtain the thickness L1 of the sound portion. L1 = (T−t) × V / 2 (1)

By applying an air pressure of 5 kgf / cm ² to the air hammer 21 with the air pressure regulator 22, the refractory brick 3 is hit with the tip 21a. Thereby, the elastic wave propagates in the refractory brick 3. The elastic wave at this time is received by the accelerometer 23, amplified by the signal amplifier 24,
The bandpass filter 25 removes noise components during blast furnace operation, and the A / D converter 26 performs A / D conversion. The A / D converted signal is used as an averaging processing unit of the signal processor 27.
It is given to 27a and the S / N ratio is improved by the addition and averaging of a predetermined number of times.

The thickness measuring unit 27b has an S / N ratio as shown in FIG.
The power spectrum of the signal with the improved ratio is obtained by FFT operation, the frequency of the spectrum with the lowest frequency in the spectrum group is detected as the basic resonance frequency fr, and the substitution operation to the following formula (2) is performed to obtain the brick. The remaining thickness L2 is calculated. L2 = V / (2 · fr) (2)

Further, the signals from the thermometers 11 and 11 are heat flux meters.
The heat flux is detected by the heat transfer calculation device 12 and is applied to the heat conduction calculation device 13. The distance between the thermometers 11 and 11 is set to x1, and the distance between the outside thermometer 11 and the surface of the refractory brick 3 is usually several mm, so it is ignored. The heat conduction calculation device 13 calculates the temperature t by the distance x1 and the two thermometers 11 and 11 based on the equation (3).
Based on 1 and t2, the thickness L3 up to the eroded surface is obtained.
The erosion surface is a portion in contact with the hot metal (temperature tp: 1150 ° C) which is a heat source. L3 = {(tp-t1) / (t2-t1)} × x1 (3)

The comparison calculator 14a of the calculator 14 is a signal processor.
The thickness L1 obtained in 10; the thickness L2 obtained in the signal processor 27; and the thickness L3 up to the erosion surface obtained in the heat conduction calculation device 13 are compared with preset values. Further, L2-L1 and L3-L2 are appropriately calculated and compared with a preset numerical value. Then, the wear degree evaluator 14b evaluates the wear degree on the basis of these comparison results, for example, in five stages.

The comparison values set in the comparison calculator 14a are shown below. L1: 0,250,500,750,1000 (mm) L2: 0,250,500,750,1000 (mm) L3: 0,250,500,750,1000 (mm) L2-L1: 0,50, 100, 250, 500, 750, 1000
(Mm) L3-L2: 0, 50, 100, 250, 500, 750, 1000
(Mm) Then, an example of evaluation in a five-stage evaluation in which "1" is no wear and "5" is wear limit is given below. (I) 250 mm <L1 <500 mm L2> 1000 mm L3> 1000 mm 500 mm <L2-L1 <750 mm 250 mm <L3-L2 <500 mm In this example, there is a crack inside the refractory brick 3 (L
1) Since the thickness L2 to the embrittlement portion remains 1000 mm or more, the distance (L3-L2) from the embrittlement portion to the heat source is also secured to be a predetermined value (250 mm) or more. Therefore a wear rate evaluator
14b is evaluated as a degree of wear of 3.

(II) 500 mm <L1 <750 mm 500 mm <L2 <750 mm 750 mm <L3 <1000 mm 0 mm <L2-L1 <50 mm 50 mm <L3-L2 <100 mm In this example, L2-L1 is predetermined. Since it is smaller than the value (50 mm), there are no cracks, but the thickness up to the embrittlement (L
1 or L2, whichever is smaller, is the predetermined control value (75
0 mm) or less. The distance from the embrittlement to the heat source (L
3-L2) is also a predetermined value (100 mm) or less. Therefore, the wear evaluation is a wear level of 4, which requires measures such as an operation to promptly protect the refractory material.

The evaluation result obtained in the arithmetic unit 14 is given to the output device 15, and the output device 15 outputs the evaluation result by means of display on the display, print output or the like.

In FIG. 1, the iron skin 1 and the stamp material 2 are opened, and the tip of the ultrasonic probe 5 is inserted into the opening 4 for measurement, so that the propagation time of ultrasonic waves is accurately measured. However, if the stamp material 2 has good properties,
You may open and measure only the iron skin 1. In addition, the contact state of the iron skin 1, the stamp material 2 and the refractory brick 3 is good,
If there is no defect such as peeling in each part, hit the surface of the iron skin 1 with a hammer as long as it is possible to detect the reflected signal, and generate 20 kH
The thickness L1 may be obtained by using an elastic wave of z or more for measurement.
Further, in the above-described embodiment, an elastic wave of 5 kHz or less is generated by the air hammer 21 in order to measure the thickness L2. For example, a sinusoidal excitation force is applied to the refractory brick 3 by means such as an exciter. It may be configured to. In this case, the mechanical impedance is measured, the resonance frequency is obtained from the peak value, and the brick residual thickness L2 is obtained.

Mode example 2. FIG. 5 is a block diagram showing an apparatus for carrying out the refractory management method according to the present invention. L
1, L2, L3 are measured at a plurality of (eight in FIG. 5) measuring elements 31, ... L1, L2, L3 at each position are obtained. All the obtained data are given to the calculator 14 for comparison and examination. As a result, when the data is locally different among a plurality of locations, this location is specified and output by the predetermined output device 15.

For example, when L1 and L2 have the same value at one location and are smaller than other locations, it is considered that this location is locally eroded. Also L1, L2
Are different values and L1 is locally small, it is considered that a crack is generated at this position. Therefore, it can be judged that a partial renovation of this place is necessary. When the state is locally different like this, in one measurement,
This position is unlikely to be measured, and hot metal may flow out from this position. However, the more measurement points there are, the higher the possibility that this position will be detected and specified. Therefore, it becomes possible to manage defects such as cracks and erosion that have occurred locally, prevent partial accidents such as hot metal outflow, and operate safely for a long period of time. Become.

Note that all or part of the processing in the arithmetic unit 14 may be performed manually, and in this case, the apparatus of the first embodiment can be used.

Mode example 3. FIG. 6 is a configuration diagram showing an apparatus for carrying out the refractory management method according to the present invention, and shows only a portion related to a computing unit. The calculator 14 has L1 and L
A measurement value storage unit 14c that stores the data of L2 and L3 in association with each measurement date, a change-over-time calculation unit 14d that obtains a change over time for each of L1, L2, and L3, and a change over time. A prediction unit 14e that predicts subsequent data changes from past empirical data, a management value storage unit 14f that stores the management values of each of L1, L2, and L3, and the value predicted by the prediction unit 14e is the management value. Calculator for calculating the time point below 14
with g and.

The operation of the arithmetic unit 14 will be described. The calculated measurement data of L1, L2, and L3 obtained by the signal processors 10 and 27 and the heat conduction calculation device 13 are stored in the measurement value storage unit 14c in association with the respective measurement dates, and the temporal change calculation unit 14d. However, this data is extracted at any time and L1,
The change with time is obtained for each of L2 and L3. The predicting unit 14e predicts subsequent data changes from the temporal changes obtained by the temporal change calculating unit 14d and past empirical data, and this predicted value is stored in the management value storage unit 14f as L1. , L2, L3 each time when it falls below the control value
Calculates 14 g. It is empirically known that L1, L2, and L3 change as shown in FIG. 7, and the prediction unit 14e stores this data. The management value described above may be either one or both of a value that is generally considered to be the life and a value that needs to be repaired, as required. Other values may also be used.

L1, L accumulated in this way over time
By using the data of 2 and L3, it is possible to grasp the remaining life, the repair time, etc., prevent accidents such as hot metal outflow, and use the blast furnace efficiently. Further, all or part of the processing in the arithmetic unit 14 having the configuration as shown in FIG. 6 may be performed manually, and in this case, the device of the first embodiment can be used. Further, the measurement may be performed at a plurality of points.

[0049]

【Example】

Example 1. FIG. 8 shows the thickness L1 obtained in Example 1.
It is a schematic diagram of the refractory brick 3 which shows L2 and L3 and the result of having verified the measurement place by core boring. The values used for each arithmetic expression and the arithmetic results are listed. The frequency of ultrasonic waves
It is 100 kHz. L1: T = 415 μsec, t = 30μsec, V = 2800m / sec L1 = (T-t) × V / 2 ... (1) = (415-30) × 10 -6 × 2800 × 10 3/2 ≒ 540 mm L2: fr: 1.37 kHz L2 = V / (2 · fr) (2) = 2800 / (2 × 1.37) ≈1020 mm L3: t1 = 100 ° C., t2 = 171 ° C., x1 = 100 mm L3 = {( tp-t1) / (t2-t1)} × x1 (3) = {(1150-100) / (171-100)} × 100 ≈ 1480 mm L2-L1 = 1020-540 = 480 mm L3-L2 = 1480-1020 = 460 mm.

Since L2-L1 is larger than the predetermined value (50 mm), it is determined that there is a crack, and the position is the ultrasonic measurement value L1 = 540 mm, and the accuracy is 540 mm which is the result of actual measurement by core boring. I am measuring well. Further, the brick thickness L2 from the resonance frequency due to brick impact to the embrittlement portion is 1020 mm, and the measured value of 980 mm is accurately measured. Further, the thickness L3 from the measured value of the thermometer to the heat source is 1480 mm, which is a little less accurate than the brick residual thickness of 1300 mm including the solidified portion by actual measurement, but the approximate total brick residual thickness is estimated. Can be said.

The comparison calculator 14a outputs the following result as a result of the predetermined comparison. 500 mm <L1 <750 mm L2> 1000 mm L3> 1000 mm 250 mm <L2-L1 <500 mm 250 mm <L3-L2 <500 mm From the above results, the wear degree evaluator 14b evaluates the wear degree to be 2.

Example 2. FIG. 9 is a schematic diagram of the refractory brick 3 showing the thicknesses L1, L2 and L3 obtained in Example 2 and the results of verification by core boring at the measurement locations. The values used for each arithmetic expression and the arithmetic results are listed. The frequency of ultrasonic waves is 100 kHz. L1: T = 910 μsec, t = 30μsec, V = 2800m / sec L1 = (T-t) × V / 2 ... (1) = (910-30) × 10 -6 × 2800 × 10 3/2 ≒ 1230mm L2: fr: 1.1 kHz L2 = V / (2 · fr) (2) = 2800 / (2 × 1.1) ≈1270 mm L3: t1 = 130 ° C., t2 = 204 ° C., x1 = 100 mm L3 = {(tp -T1) / (t2-t1)} × x1 (3) = {(1150-130) / (204-130)} × 100 ≈ 1380mm L2-L1 = 1270-1230 = 40mm L3-L2 = 1380 -1270 = 110 mm.

Since L2-L1 was smaller than the predetermined value (50 mm), it was judged that there was no crack, and no crack actually occurred. The ultrasonic thickness L1 (1230 mm) accurately represents the thickness 1240 mm up to the embrittlement portion. The brick thickness L2 from the resonance frequency due to brick impact to the embrittlement part is 1270
mm, and the measurement accuracy is slightly lower than the ultrasonic measurement value. This is the frequency of the elastic wave used in ultrasonic waves 100 k
Hz is more than the frequency used in the resonant frequency measurement
It is estimated to be about 100 times higher. Furthermore, the thickness L3 from the measurement value of the thermometer to the heat source is 1370 mm,
It shows a good agreement with the measured brick residual thickness of 1310 mm including the solidified portion, but it is speculated that this is because the thickness of the embrittled portion and the knitting of the solidified portion are relatively thin at 20 mm and 50 mm, respectively.

The comparison calculator 14a outputs the following result as a result of the predetermined comparison. L1> 1000 mm L2> 1000 mm L3> 1000 mm 0 mm <L2-L1 <50 mm 50 mm <L3-L2 <100 mm From the above results, the wear degree evaluator 14b evaluates the wear degree to be 1.

Example 3. FIG. 10 is a schematic diagram of the refractory brick 3 showing the thicknesses L1 and L2 obtained in Example 3 and the results of verification by core boring at measurement locations. The values used for each arithmetic expression and the arithmetic results are listed. The frequency of ultrasonic waves is 100 kHz. L1: T = 605 μsec, t = 30μsec, V = 2800m / sec L1 = (T-t) × V / 2 ... (1) = (605-30) × 10 -6 × 2800 × 10 3/2 ≒ 810 mm L2: fr: 1.15 kHz L2 = V / (2 · fr) (2) = 2800 / (2 × 1.15) ≈1220 mm Further, L2-L1 = 1220-810 = 410 mm.

Since L2-L1 is larger than a predetermined value (50 mm), it is judged that there is a crack. However, although the crack does not actually occur, there is a deteriorated portion where many minute cracks are present in front of the embrittled portion. Existed. The thickness L1 (810 mm) by ultrasonic waves is measured up to this deteriorated part, and the brick thickness L2 up to the embrittlement part measured from the resonance frequency due to brick impact
(1220 mm) indicates the thickness up to the embrittlement part. The measured values are 830 mm and 1200 mm, respectively, and the accuracy is good. In this way, when L2-L1 larger than the predetermined value is larger than the predetermined value, it can be said that there is some ultrasonic reflection source (such as a crack) in front of the embrittled portion.

The comparison calculator 14a outputs the following result as a result of the predetermined comparison. 750 <L1 <1000 mm L2> 1000 mm 250 mm <L2-L1 <500 mm From the above results, the wear degree evaluator 14b evaluates the wear degree to be 2.

Items that can be measured and discriminated by the present invention are summarized below. L2-L1 ... Presence or absence of crack or deteriorated part L1 ... Thickness to deteriorated part or embrittled part L2 ... Thickness to embrittled part L3 ... Thickness to heat source including solidified part

Example 4. The present embodiment corresponds to the above-described second embodiment. That is, as shown in FIG. 6, the above-mentioned L1, L2, and L3 were measured at eight locations by eight measuring elements 31, ... Arranged at equal intervals in the furnace bottom circumferential direction in the blast furnace. L1 and L2 had a control value (A) of 1250 mm or less and L3 had a control value (B: B> A) of 1000 mm or more only at one location. In all other directions, L1, L2 and L3 were all above the control value. Therefore, it is determined that bricks need to be partially transshipped at locations where L1 and L2 were below the control values.

FIG. 11 shows L1, L2, L in this portion.
It is a schematic cross section which shows the calculated measurement value of 3, and the measured value and control value together. In the figure, L1, L2, and L3 indicate calculated measurement values, and A and B indicate control values. The actual measurement values are also shown. When the bricks removed by transshipment were actually checked, it was L1 ... 1240 mm (<A) L2 ... 1270 mm (> A), which is a very dangerous state. By this transshipment, it was possible to prevent accidents such as hot metal outflow. Further, upon disassembling and investigating at this point, the measured value of L3 was 1310 mm (<B), and it was found that there was a large error from the calculated measured value. It is considered that this is because the thermal conductivity greatly changed due to the deterioration of the brick.

Example 5. This embodiment corresponds to the above-described third embodiment. That is, in the device having the arithmetic unit 14 having the configuration shown in FIG. 6, the control value (A) of L1 and L2 is set to 1250 mm and the control value (B) of L3 is set to 1300 mm in order to implement the repair. In the blast furnace 12 years after burning at that time, the erosion progresses at xmm / year from the 7th year after burning and at ymm / year from the 7th year to 12th year (Fig.
12) Based on past empirical data, future erosion will start from the 7th year
Assuming the same speed as in the 12th year, the number of years a until the repair is calculated by the following formula. There is no crack here L
The case where 1 = L2 is shown. (Brick base thickness) -7x- (5 + a) y ≤ A In the above formula, the brick base thickness is 1500mm, x is 24mm, and y is 10
In mm, a is 15 years, that is, it is estimated that the thickness will need to be improved after 3 years. The predicted value thus obtained was found to be very effective, with an error of 5% or less with respect to the thickness L2 up to the embrittlement layer in the disassembly study at the time of repair.

[0062]

As described above, the method of evaluating the wear of a refractory according to the present invention and the apparatus used for carrying out the method can be applied to a sound part from the round-trip propagation time of an elastic wave of 20 kHz or higher, which is a relatively high frequency, in the refractory. Embrittlement of refractory by determining the thickness to the reflection source, which is a crack, crack or embrittlement, and propagating a relatively low elastic wave of 5 kHz or less and detecting the resonance frequency of the refractory. To the known heat source temperature from the temperatures and distances near the outer surface of at least two locations, and the thickness to the heat source is calculated. By determining the degree of wear of the refractory, it is possible to accurately grasp the remaining thickness and the internal state of the refractory and evaluate the degree of wear of the refractory with high accuracy and reproducibility.

In the refractory management method according to the present invention,
By performing measurement at multiple points and detecting local abnormalities, it can be used for partial repair. Furthermore, by predicting the subsequent erosion situation from past time-course data, it is possible to predict the remaining life and the time of repair, etc.
The present invention has excellent effects.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an apparatus for carrying out a method for evaluating wear and tear of a refractory material according to the present invention.

FIG. 2 is a configuration diagram showing an apparatus for carrying out the method for evaluating the wear and tear of a refractory material according to the present invention.

FIG. 3 is a waveform diagram showing elastic waves detected by the ultrasonic probe shown in FIG.

FIG. 4 is a diagram showing a power spectrum obtained by a thickness measuring unit shown in FIG.

FIG. 5 is a block diagram showing a main part of a refractory management device according to a second example.

FIG. 6 is a block diagram showing a main part of a refractory management apparatus according to a third embodiment.

FIG. 7 is a graph showing changes over time of empirically known L1, L2, and L3.

FIG. 8 is a schematic diagram of a refractory brick showing each thickness obtained in Example 1 and a result of verification by core boring at a measurement place.

FIG. 9 is a schematic diagram of a refractory brick showing each thickness obtained in Example 2 and the result of verification by core boring at a measurement place.

FIG. 10 is a schematic view of a refractory brick showing the respective thicknesses obtained in Example 3 and the results of verification by core boring at measurement locations.

FIG. 11 is a schematic cross-sectional view showing a calculated measurement value, an actual measurement value, and a control value of L1, L2, and L3 in a certain portion.

FIG. 12 is a graph showing changes with time of L1, L2, and L3, and predicted values.

[Explanation of symbols]

1 iron skin 2 stamp materials 3 refractory bricks 4 Openings 5 Ultrasonic probe 5a Contact medium 6 pulsar 7,24 signal amplifier 10, 27 signal processor 10a, 27a Averaging processor 10b, 27b Thickness measurement section 8,25 bandpass filter 9,26 A / D converter 11 thermometer 12 Heat flux meter 13 Thermal conductivity calculator 14 arithmetic unit 14a Comparison calculator 14b Wear rate evaluator 14c Measured value storage 14d Change over time calculation unit 14e Predictor 14f Control value storage 14g calculator 15 Output device 21 air hammer 21a Tip 22 Air pressure regulator 23 Accelerometer 31 Measuring element 32 furnaces

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C21B 7/24 306 F27D 21/00 G01B 17/00

Claims (11)

(57) [Claims] 1. A method of measuring the thickness of a refractory material lined on the inside of an iron shell of a furnace, determining the internal state of the refractory material, and evaluating the degree of wear of the refractory material due to the heat source in the furnace from these results. Therefore, the first elastic wave is propagated inward from the outer surface of the refractory, the reflected wave at the reflection source in the refractory is detected, and the first elastic wave is required for the round trip from the outer surface to the reflection source. The thickness L1 from the outer surface to the reflection source is calculated using the time, and a second elastic wave having a lower frequency than the first elastic wave is propagated from the outer surface to the inner side to determine the resonance frequency of the refractory. The thickness L2 from the outer surface of the refractory to the embrittlement portion is calculated based on the resonance frequency, and the temperature of at least two locations near the outer surface of the refractory at predetermined intervals in the thickness direction is measured. Then, using this temperature measurement value, Calculating the thickness L3 from the surface to the heat source, using said thickness L2 of up to a thickness L1 and the embrittlement of the reflection source, or the thickness L 3 of the to a thickness L2 and the heat source to the embrittlement portion A method for evaluating the wear of a refractory, which comprises determining the degree of wear of the refractory using the method. 2. The method for evaluating wear of a refractory according to claim 1, wherein the frequency of the first elastic wave is 20 kHz or more and the frequency of the second elastic wave is 5 kHz or less. 3. A difference between a thickness L1 up to the reflection source and a thickness L2 up to the embrittlement portion is obtained, and the difference is used to determine whether the reflection source is a crack, a crack portion or an embrittlement portion. The method for evaluating the wear of a refractory according to claim 1 or 2, characterized by making a judgment. 4. The method for evaluating the wear of a refractory according to claim 1, 2 or 3 is carried out at a plurality of points in a furnace to obtain the L1, L
A refractory management method characterized by detecting and specifying a place where 2 or L3 is a predetermined value or less. 5. The L1, L2 or L3 obtained by using the method for evaluating wear of refractory according to claim 1, 2 or 3 is calculated with time, and a change with time of this value is obtained, A method for managing a refractory material, which comprises predicting a subsequent change from the change and calculating a time point at which the predicted value falls below a predetermined value. 6. A device for measuring the thickness of a refractory material lined inside the iron shell of a furnace, determining the internal state of the refractory material, and evaluating the wear degree of the refractory material due to the heat source in the furnace from these results. And a means for propagating the first elastic wave from the outer surface of the refractory toward the inner side, a means for detecting a reflected wave at a reflection source in the refractory, and the elastic wave from the outer surface to the reflection source. Means for calculating the thickness L1 from the outer surface to the reflection source using the time required for the round trip, and means for propagating a second elastic wave having a lower frequency than the first elastic wave inward from the outer surface. A means for detecting the resonance frequency of the refractory, a means for calculating the thickness L2 from the outer surface of the refractory to the embrittlement portion based on the resonance frequency, and a predetermined distance in the thickness direction near the outer surface of the refractory. Less buried at intervals Both of them are provided with two thermometers, and a means for calculating the thickness L3 from the outer surface to the heat source by using the measured value by the thermometers, a wear resistance evaluation apparatus for a refractory. 7. The thickness L1 to the reflection source and the thickness L2 to the embrittlement portion are used, or the thickness to the embrittlement portion is used.
Wear evaluation apparatus according to claim 6 refractory according characterized in that it comprises means for determining the wear of the refractories by using L2 and the thickness L 3 to the heat source. 8. The refractory wear evaluation apparatus according to claim 6, wherein the first elastic wave has a frequency of 20 kHz or higher and the second elastic wave has a frequency of 5 kHz or lower. 9. A means for obtaining a difference between a thickness L1 to the reflection source and a thickness L2 to the embrittlement portion, and the reflection source is a crack, a crack portion or an embrittlement portion using the difference. The refractory wear evaluation apparatus according to claim 6, 7 or 8, further comprising: 10. A refractory wear evaluation apparatus according to claim 6, which is to be installed at a plurality of locations in a furnace, and a location where L1, L2 or L3 is below a predetermined value is detected and specified. A refractory management apparatus comprising: 11. The L calculated with time using the refractory wear evaluation apparatus according to claim 6.
1, a means for storing L2 or L3, a means for obtaining a temporal change of this value, a means for predicting a subsequent change from the temporal change, and a means for calculating a time point at which the predicted value falls below a predetermined value. A refractory management device comprising: