JPH08261741A - Measuring method for blast furnace refractory thickness - Google Patents

Abstract

PURPOSE: To provide a technology for measuring remaining thickness of refractory for blast furnace without using thermocouple, coaxial cables and radioactive elements. CONSTITUTION: Surrounding the bottom part 2 of blast furnace 1, position detection type radiation detectors 11 to 13 are arranged. By selectively making use of muon among various cosmic-rays and measuring the intensity of the muon after penetrating the furnace bottom part 2 with the position detection type radiation detectors 11 to 13, the thickness of the bottom part 2 specifically, of refractory 3 is measured quantitatively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for measuring the remaining thickness of refractory on the wall or bottom of a blast furnace.

[0002]

2. Description of the Related Art A blast furnace (blast furnace) is, as is well known, a furnace for melting pig iron ore to produce pig iron, and is a kind of cylindrical vessel having a thick iron shell lined with refractory for blast furnace. Since the erosion due to the hot metal is significant from the pool of the blast furnace to the bottom of the furnace,
A refractory material with excellent corrosion resistance is wound on the furnace wall and furnace bottom in a sufficient thickness. On the other hand, the operating life of the blast furnace has been over 20 years due to recent improvements in operating methods and repair techniques. Along with this, a technique for accurately measuring damage to the refractory at the bottom of the furnace has been required. That is, because the bottom of the furnace cannot be repaired during operation, the wear of refractory at the bottom of the furnace affects the life of the entire blast furnace.If the wear status can be grasped, titanium oxide should be added as appropriate. Measures can be taken to extend the life of refractories at the bottom of the furnace.

Techniques for measuring the amount of damage or residual refractory material at the bottom of the furnace are disclosed in Japanese Patent Laid-Open No. 63-100315, "Method for understanding wear state of refractory wall of high-temperature furnace", Japanese Patent Laid-Open No. 49-133.
No. 207 “Method and apparatus for detecting thickness of furnace wall”,
Japanese Unexamined Patent Publication No. 58-27002, "Method of measuring thickness of refractory material" and method of embedding radioactive isotope such as Co60 in refractory material at bottom of furnace are proposed. these~
The technology will be summarized and explained with the following figure.

FIG. 8 is a diagram showing a conventional method for measuring the amount of damage or remaining refractory material at the bottom of the furnace. In the above and the figures, thermometers 101 (plurality) are connected to the refractory material 102 at the bottom of the furnace.
The remaining amount of the refractory material 102 is estimated from the change in the measured temperature. That is, the refractory material 102 becomes thinner as it operates, and the indication value of the thermometer 101 becomes higher. In the above and in the figures, the coaxial cable 104 is embedded in the refractory material 102, and an electric pulse is input from one end of the coaxial cable 104, and the time taken for the electric pulse to be reflected and returned at the other end is measured. This time is coaxial cable 104
Since the coaxial cable 104 is proportional to the refractory 1
The shorter the erosion of 02, the shorter the propagation time.

In the above and in the drawings, a hole 106 is opened in the furnace body iron shell 105, a metal rod 107 is inserted into the hole 106, and the tip of the metal rod 107 is brought into contact with the refractory material 102.
A hammer 108 strikes the other end to generate a vibration wave, and the acceleration pickup 109
It is to detect with. Above and in the figure,
When a radioactive isotope 111 (referred to as a radioactive element 111) is embedded in the refractory 102 at the time of building a furnace and the erosion progresses to the radioactive element 111, the radioactive element 111 dissolves in the hot metal and disappears. Then, when I examined it with a radiation counter from outside the reactor, I found that there was no radioactive element 111,
The erosion position can be known.

[0006]

However, the above is to indirectly measure the heat conduction of the refractory material 102,
Since the thermal conductivity of the refractory material 102 changes depending on the ambient temperature, the estimation accuracy is not good. Further, since the thermometer 101 is used for a long period of time and the setting environment (pressure, temperature, etc.) is not good, there is a risk of deterioration, and there is a possibility that reliable measurement may not be possible at an important end of the reactor life. .

Although the above is a method for directly measuring the remaining amount of the refractory material 102, only information on the position of the coaxial cable 104 embedded at the time of furnace construction can be obtained. That is, the situation of the part away from the coaxial cable 104 is unknown. Further, the coaxial cable 104 may be deteriorated by the influence of corrosive gas in the furnace.

The above is the fact that the refractory material 102 is a material that is extremely difficult for vibration waves such as ultrasonic waves to pass through, and the iron skin 105.
Since a vibration wave is also reflected at the boundary 112 between the refractory 102 and the refractory 102, a plurality of vibration waves are mixed with each other, and as a result, the reliability of measurement is deteriorated, which is not a practical measurement method.

The above is point measurement, that is, radioactive element 11
Refractory 10 because only the buried position of 1 can be measured
It is not possible to continuously know the progress of erosion of 2. Further, in order to use the radioactive element 111, safety and hygiene control is extremely important, and this burden is not light, so that it has not been used in recent years. Therefore, the object of the present invention is to
It is to provide a method for measuring the bottom thickness that is superior to

[0010]

In order to solve the above problems, the present invention provides at least three position detection type radiation detectors outside the blast furnace at right angles to the plane of the position detection type radiation detector. Line penetrates the blast furnace, and a plurality of position detection type radiation detectors are arranged in parallel with each other at regular intervals.

The first data of the muon intensity is calculated by calculating the intensity of the muon which penetrates the blast furnace and penetrates the plurality of position detection type radiation detectors in a certain direction within a certain time from the incident angle information of the muon. Then, the second data of the muon intensity flying from a certain direction is similarly calculated from the incident angle information of the muon after the lapse of a predetermined time, and the intensity of the muon in the blast furnace changes as the lining furnace refractory of the blast furnace changes, The thickness of the refractory of the blast furnace is measured based on the change in the muon strength.

A muon is a type of cosmic ray that travels from the universe through the Bern-Allen belt and the atmosphere to reach the surface of the earth.
Explain the reason for choosing muon from the many cosmic rays. Muons are elementary particles that have the longest lifetime next to neutrons, the weight is about 200 times that of electrons, and have + and-charges. Only strong electromagnetic interaction with other particles causes them to interact strongly. There is no (nuclear power). Therefore, compared with pions, protons, and other materials that have both electromagnetic and nuclear interactions, the penetrating force is high and the interaction is easy to analyze. For this reason, I chose muon. The identification is to confirm that the event A and the event B are the same.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 (a) and 1 (b) are explanatory views of the arrangement of a position detection type radiation detector according to the present invention, in which a furnace bottom 2 of a blast furnace 1 is a steel shell (specific gravity 7.8, thickness 70 mm, for example) 3 It is a carbon refractory material (specific gravity: about 2.3) 4 lined. The inside of the refractory material 4 is called a hot water pool, in which hot water and coke mixed hot water is pooled. Since the average specific gravity of the coke is 0.7, the average specific gravity of the mixed hot water is about 4.0.

A position detection type radiation detector set 10 (hereinafter abbreviated as "radiation detector set 10"), that is, # 1 position detection type radiation detector 1 is provided on the side of the furnace bottom 2.
The three plastic position-detection-type radiation detectors 1, 1, # 2 position-detection-type radiation detectors 12 and # 3 position-detection-type radiation detectors 13 pass through the furnace bottom part 2 with straight lines parallel to each other and orthogonal to the plane. Place it in the position you want. In the figure, the alternate long and short dash line μ is the trajectory of the muon.

A method of measuring the thickness of the bottom of the blast furnace using the above-mentioned position detection type radiation detector will be described below. FIG. 2 is an explanatory view of an embodiment of the present invention, in which # 1 position detection type radiation detector 11, # 2 position detection type radiation detector 12 and # 3 position detection type radiation detector 13 are arranged. The incident angle α1 is calculated from the 1-position detection type radiation detector 11 and the # 2 position detection type radiation detector 12, and the # 2 position detection type radiation detector 12 and the # 3 position detection type radiation detector 13 are calculated.
The incident angle α2 is calculated from and the average incident angle α3 is calculated from these.
(= (Α1 + α2) / 2) can also be obtained.

FIG. 3 is a system configuration diagram of three position detection type radiation detectors. When the contents described in FIG. 2 are summarized, the position detector 11a attached to the # 1 position detection type radiation detector 11 is used for incidence. The position is detected, the incident position is detected by the position detector 12a attached to the # 2 position detection type radiation detector 12, and the incident position is detected by the position detector 13a attached to the # 3 position detection type radiation detector 13. The incident angle determination circuit 14 determines the incident angle based on these pieces of information, and the muon intensity determiner 16 determines the muon intensity after a predetermined period (for example, 50 days).

FIG. 4 is an attenuation diagram of muons at the bottom of the blast furnace during furnace construction. The vertical axis represents the muon intensity and the horizontal axis represents the distance. It is assumed that muons are incident on the bottom of the furnace from the right side of the figure as indicated by the chain line μ. That is, the muon penetrates the bottom of the furnace in the order of the iron skin 3R, the refractory 4R, the basin 5, the refractory 4L, and the iron skin 3L, and then the radiation detector set 10
Incident on. The “first data of muon intensity” is measured by the radiation detector set 10. The thick broken line shows the strength of the muon, and the refractory materials 4R and 4L have relatively small specific gravity, so the muon damping is small. On the contrary, the pool 5 is a mixture of hot metal and coke, so the muon damping is large. Is big.

FIG. 5 is a decay diagram of muons at the bottom of the blast furnace after a lapse of time, showing that the refractories 4R and 4L were eroded by hot metal or the like and the inner surface retreated from the position indicated by the imaginary line to the position indicated by the solid line. Indicates. Refractory 4R with small specific gravity,
Since 4L is replaced by the pool 5 having a large specific gravity, the "second muon intensity data" measured by the radiation detector set 10 is smaller than the first muon intensity data.

By the way, the substance penetrating force of muons has the following relationship between the energy E and the penetrating force X (m). However, the substance was iron having a specific gravity of 7.8. X = 7.8 × 2.5 × 10 ³ ln (1.56 · E + 1) By using the above formula and changing the specific gravity of the substance, the muon required to penetrate the refractory and the pool The intensity change can be obtained.

FIG. 6 is a graph showing the relationship between the muon strength and the thickness of the refractory material. If the first data of the muon strength is measured at the time of furnace construction (maximum thickness of the refractory material), the above formula and the dimensions of each part You can also draw a curve to the right from the specific gravity. Therefore, the thickness of the refractory can be easily estimated by measuring the second data of the muon strength by the method of the present invention, for example, 5 years after the furnace is built. After that, the time for blast furnace repair can be determined by timely measurement.

7 (a) and 7 (b) are plan layout views of the radiation detector set according to the present invention. (A) is for detecting muons penetrating the center of the furnace bottom. Since the refractory 4 does not always become thin on average, a plurality of radiation detector sets 10, 10a, 10b,
10c may be arranged or one set of radiation detector sets 10 may be moved periodically. (B) shows the radiation detector set 10 arranged on the tangent to the outer circumference of the pool 5. In this way, the required number of radiation detector sets 10 may be arranged at an arbitrary position around the furnace bottom 2.

The position detection type radiation detector used in this embodiment may be a two-dimensional position detection type radiation detector. The two-dimensional position detection type radiation detector may be, for example, a multi-wire type gas detector, a drift chamber, a semiconductor detector, a scintillation counter or the like. Also,
The method of the present invention is suitable for measuring the remaining thickness of the refractory material of the blast furnace, but damages to other parts of the blast furnace, the thickness of the iron shell, and the stave when the stave is buried in the refractory material. Can be checked, that is, it can be widely applied to measurement of various parts such as the bottom of a blast furnace that is used severely.

[0023]

The present invention has the following effects due to the above configuration. The method for measuring the thickness of a blast furnace refractory according to claim 1 selectively uses muons among a number of cosmic rays, and measures the intensity after the muons penetrate the blast furnace with a position detection type radiation detector. It is possible to quantitatively measure the remaining thickness of the refractory, and it is not necessary to embed the thermocouple, the coaxial cable or the radiation element in the refractory as in the prior art, and there is no concern that the equipment will change over time. It is extremely preferable because the thickness of the blast furnace refractory can be measured at any time.

[Brief description of drawings]

FIG. 1 is a layout explanatory view of a position detection type radiation detector according to the present invention.

FIG. 2 is an explanatory view of an embodiment according to the present invention.

FIG. 3 is a system configuration diagram of three position detection type radiation detectors according to the present invention.

FIG. 4 is an attenuation diagram of muons at the bottom of the blast furnace during furnace construction according to the present invention.

FIG. 5 is a muon attenuation diagram at the bottom of the blast furnace according to the present invention after the passage of time.

FIG. 6 is a graph showing the relationship between muon strength and refractory thickness according to the present invention.

FIG. 7 is a plan layout view of a radiation detector set according to the present invention.

FIG. 8 is a diagram showing a conventional method for measuring the amount of damage or remaining refractory at the bottom of a furnace.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Blast furnace, 2 ... Furnace bottom part, 3 ... Iron shell, 4 ... Refractory material, 5 ... Hot water pool, 10 ... Position detection type radiation detector set (radiation detector set), 11 ... # 1 position detection type radiation detector 1
2 ... # 2 position detection type radiation detector, 13 ... # 3 position detection type radiation detector, 14 ... Incident angle determination circuit, 16 ... Muon intensity determination circuit, 21-24 ... Photomultiplier tube, α1 ...
Incident angle, Ls ... A line orthogonal to the plane of the position-sensitive radiation detector.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenchu Nagamine 3-10-8 Masuodai, Kashiwa City, Chiba Prefecture

Claims (1)

[Claims] 1. A position detection type radiation detector is arranged outside a blast furnace wall or a bottom part of the blast furnace, and penetrates the blast furnace within a certain period of time and a plurality of position detection type radiation detectors are set in a certain direction. The intensity of the muon penetrating from the muon is calculated from the incident angle information of the muon, and this calculated value is used as the first data of the muon intensity. Also, after a predetermined time has passed, the muon intensity that similarly flies from a certain direction from the incident angle information of the muon. Of the muon penetrating the blast furnace as the refractory lining of the blast furnace is eroded, the thickness of the refractory on the furnace wall or bottom is calculated based on the muon strength change. A method for measuring the thickness of a blast furnace refractory characterized by measuring.