JP6885806B2 - How to get information inside the blast furnace - Google Patents

Description

The present invention relates to a technique for acquiring information on the boundary position between the furnace wall and the inside of a blast furnace by detecting cosmic ray muons that have passed through a blast furnace formed of refractory bricks.

The blast furnace is made of refractory materials such as refractory bricks, and pig iron melted by high temperature is flowing in the furnace. For this reason, the refractory bricks on the inner wall surface of the furnace are scraped by the flowing pig iron and gradually become thinner, and eventually it becomes necessary to rebuild the blast furnace. In order to determine when to rebuild the blast furnace, it is necessary to measure the thickness of the refractory bricks left after being scraped by pig iron. However, it takes time and cost to stop the blast furnace in operation, so it is desirable to be able to measure the thickness of the remaining refractory bricks while the blast furnace is operating, if possible.

Therefore, as a method that can realize such a thing, a method of detecting the position of the boundary between the pig iron and the refractory brick in the blast furnace by using the cosmic ray muon has been proposed (for example, Patent Document 1). Here, cosmic ray muons are a type of elementary particles that are generated by cosmic rays colliding with the atmosphere of the earth and are constantly falling on the ground, and while they can permeate substances with high penetrating power, they have a mass. When a large substance is permeated, the amount of permeation decreases according to the mass and permeation distance. Since pig iron has a larger mass than the refractory brick, the permeation amount of muon is greatly reduced in the part where the pig iron is present in the blast furnace as compared with the part of the refractory brick. Therefore, if muons that have penetrated through the blast furnace are detected and the location where the amount of muons permeated (that is, the detection frequency) changes significantly is searched, the position of the boundary between the pig iron and the refractory brick can be determined while the blast furnace is still in operation. It can be detected and the thickness of the remaining refractory bricks can be determined.

JP-A-2007-121202

However, with the above-mentioned proposed technique, it is difficult to detect the boundary position between the pig iron and the refractory brick in the blast furnace with sufficient accuracy, and therefore it is difficult to detect the thickness of the refractory brick with sufficient accuracy. There was a problem. This is due to the following reasons.

First, in order to detect the position where the muon detection frequency changes, it is necessary to measure the detection frequency accurately in the first place, and for that purpose, it is necessary to detect a large number of muons to the extent that they are statistically meaningful. .. However, cosmic ray muons fall only at a rate of about 1 per minute per square centimeter area, so it takes a long time to detect a large number of muons that are statistically meaningful. Will be. Therefore, when the analysis is performed using the detection results obtained in a short time, it becomes impossible to sufficiently secure the statistical accuracy, and it becomes difficult to accurately determine the position where the detection frequency changes. In addition, since a transition layer in which pig iron and refractory bricks coexist is formed in the portion where the pig iron flowing in the blast furnace and the refractory bricks are in contact with each other, there is no clear boundary in the first place. For this reason, it is difficult to detect the boundary position between the pig iron and the refractory brick in the blast furnace with sufficient accuracy by the conventional technique, and therefore it is difficult to detect the thickness of the refractory brick with sufficient accuracy. there were.

The present invention has been made to solve the above-mentioned problems, and it is to detect the boundary position between the pig iron and the refractory brick in the blast furnace with sufficient accuracy, and to detect the thickness of the refractory brick with sufficient accuracy. The purpose is to provide technology that enables

In order to solve the above-mentioned problems, the method for acquiring information in the blast furnace of the present invention adopts the following configuration. That is,
By detecting cosmic ray muons that have passed through the blast furnace formed of refractory bricks using a detector installed away from the outer surface of the blast furnace, the boundary position between the furnace wall of the blast furnace and the inside of the furnace is detected. It is a method of acquiring information in the blast furnace to acquire information about
A detection frequency acquisition step of acquiring the detection frequency of the cosmic ray muon that has passed through the blast furnace and reached the detector for each arrival angle of the cosmic ray muon with respect to the detector.
Among the plurality of arrival angles at which the measured values of the detection frequencies were obtained, the cosmic ray muon is a furnace at which the furnace wall of the blast furnace is permeated but the inside of the blast furnace is not permeated. A step of selecting at least a predetermined number of wall arrival angles and a furnace wall arrival angle selection step.
A prediction formula generation step of generating a prediction formula for predicting the detection frequency with respect to the arrival angle based on the actually measured values of the detection frequencies obtained at the plurality of furnace wall portion arrival angles.
It is provided with a boundary position determining step of determining the boundary position between the furnace wall and the inside of the furnace based on the deviation between the predicted value obtained by the prediction formula and the actually measured value obtained for each arrival angle. It is a summary.

In the method for acquiring information in the blast furnace of the present invention, the cosmic ray muons are transmitted through the furnace wall of the blast furnace from the detection frequency of the cosmic ray muons obtained for each reaching angle, but are transmitted through the furnace of the blast furnace. At least a plurality of predetermined arrival angles (furnace wall arrival angles) are selected. Then, after generating a prediction formula for predicting the output frequency from the arrival angle based on the measured value of the detection frequency obtained from the furnace wall arrival angle, the prediction value obtained by the prediction formula and each arrival angle are obtained. The boundary position between the furnace wall and the inside of the furnace is determined based on the deviation from the measured value.

Cosmic ray muons are transmitted through the furnace wall of the blast furnace, but not inside the furnace of the blast furnace. Within the range of the reaching angle, the detection frequency of cosmic ray muons is considered to change in a similar tendency. Therefore, it can be predicted using a prediction formula. Conversely, the measured values that deviate from the prediction formula can be considered that the cosmic ray muons also pass through the inside of the blast furnace. From this, by using the deviation between the predicted value obtained from the prediction formula and the measured value obtained for each arrival angle, the boundary position between the furnace wall and the inside of the furnace can be accurately determined, and the thickness of the refractory brick can be determined. Can be detected with high accuracy.

Further, in the above-described method for acquiring information inside the blast furnace of the present invention, prior to selecting a plurality of furnace wall portions, the space is based on the outer shape of the blast furnace and the positional relationship between the blast furnace and the detector. The reach angle at which the line muon penetrates the outermost part of the furnace wall (outermost reach angle) may be determined. Then, a plurality of predetermined arrival angles may be selected as the furnace wall portion arrival angle from the outermost arrival angle toward the inside of the blast furnace.

The reaching angle at which the cosmic ray muon penetrates the outermost part of the furnace wall (outermost reaching angle) can be accurately determined. Furthermore, it can be considered that cosmic ray muons do not pass through the inside of the blast furnace from the outermost part of the furnace wall to a certain angle range. Therefore, if a plurality of predetermined arrival angles are selected as the furnace wall arrival angles from the outermost arrival angle toward the inside of the blast furnace, the furnace wall arrival angles can be easily and correctly selected. Is possible.

Further, in the above-described method for acquiring information in the blast furnace of the present invention, prior to selecting a plurality of furnace wall portion reaching angles, the measured value of the detection frequency obtained for each reaching angle is measured by the outer shape of the blast furnace or the blast furnace. The correction may be based on at least one of the structures adjacent to.

The outer shape of the blast furnace and the structures adjacent to the blast furnace affect the detection frequency of cosmic ray muons. Furthermore, since the outer shape of the blast furnace and the structure adjacent to the blast furnace can be easily measured in size and position, the arrival angle of cosmic ray muons that affect the detection frequency and the size that affects the detection frequency are large. You can estimate the size and so on. Therefore, if the measured value of the detection frequency obtained for each arrival angle is corrected based on the result of such estimation, the boundary position between the furnace wall and the inside of the furnace can be determined more accurately. Therefore, it is possible to detect the thickness of the refractory brick with higher accuracy.

Further, in the above-described method for acquiring information in the blast furnace of the present invention, the detection frequency per unit solid angle may be acquired in the direction of the reaching angle.

This makes it possible to suppress fluctuations in the detection frequency due to the installation angle of the detector, which is preferable. For example, when replacing the detector to continue detection or comparing with past detection results, the detection frequency may change due to the fact that the detectors are not installed at the same angle. .. In particular, when a substantially flat detector is used, it is easily affected by the installation angle. Therefore, if the detection frequency per unit solid angle in the direction of the reaching angle is acquired, the detection frequency avoiding the influence of the installation angle can be acquired even if the installation angle of the detector is different. It is more preferable because it enables comparison with and integration of detection results.

Further, in the above-described method for acquiring information in the blast furnace of the present invention, the boundary position between the furnace wall and the inside of the furnace in the blast furnace may be determined as follows. First, when generating the prediction formula, the least squares error with the measured value at the furnace wall arrival angle is calculated. Then, the boundary position may be determined by obtaining the deviation between the predicted value by the prediction formula and the actually measured value obtained for each arrival angle and comparing this deviation with the least squares error.

In this way, the boundary position between the furnace wall and the inside of the furnace in the blast furnace can be determined more rationally, and the thickness of the refractory brick can be detected with high accuracy.

It is explanatory drawing of the detector 10 which detects the cosmic ray muon which has passed through the blast furnace 1. It is explanatory drawing about the method of arranging the detection frequency of a cosmic ray muon based on the arrival angle with respect to a detector 10. It is explanatory drawing which illustrated the relationship between the reaching angle of a cosmic ray muon with respect to a detector 10 and the path of a cosmic ray muon which has passed through the blast furnace 1. It is explanatory drawing which shows that the attenuation amount of a cosmic ray muon differs depending on the path which has passed through the blast furnace 1. It is explanatory drawing which showed the relationship between the reaching angle of a cosmic ray muon with respect to a detector 10 and the attenuation amount of a cosmic ray muon. It is explanatory drawing about the relationship between the attenuation amount of a cosmic ray muon and the detection frequency of a cosmic ray muon. It is explanatory drawing which showed the principle of detecting the boundary position between the furnace wall 1b and the inside 1a of the blast furnace 1 based on the detection frequency of the cosmic ray muon which has passed through the blast furnace 1. It is explanatory drawing which conceptually showed the internal state of the blast furnace 1 which is the detection target of the boundary position. It is explanatory drawing which illustrated the detection frequency actually measured in the blast furnace 1 to be detected. It is a flowchart which showed the first half part of the boundary position detection processing of this Example. It is a flowchart which showed the latter half part of the boundary position detection processing of this Example. It is explanatory drawing which showed the state of selecting the furnace wall part measured value from the measured value of the detection frequency. It is explanatory drawing which showed the state of comparing the predicted value of the detection frequency obtained from the actual measurement value of a furnace wall part, and the actual measurement value obtained inside the furnace rather than the actual measurement value of a furnace wall part. It is explanatory drawing which illustrated the result of having detected the boundary position between the furnace wall 1b and the inside of a furnace 1a by the boundary position detection process of this Example. It is explanatory drawing which shows a part of the advantage which the boundary position detection processing of this Example has. It is explanatory drawing which illustrated the case where it is necessary to correct the measured value of the detection frequency. It is explanatory drawing of the modification about the modification which corrects the measured value of the detection frequency.

Hereinafter, examples will be described in order to clarify the contents of the present invention described above.
A. Device configuration :
FIG. 1 is an explanatory diagram of a detector 10 that detects cosmic ray muons that have passed through the blast furnace 1. FIG. 1A shows a state in which the detector 10 is installed in the blast furnace 1 to be posted, and FIG. 1B shows a schematic shape of the detector 10. As shown in FIG. 1A, the blast furnace 1 is a large structure formed by stacking refractory materials such as refractory bricks in an annular shape, and the inside of the furnace wall 1b made of refractory bricks or the like is circular. The inside of the furnace 1a in the cross section is formed. The upper end of the blast furnace 1 is open, and when iron ore, coke, etc. are put in from here and heated in the furnace 1a, pig iron melted from the iron ore due to high temperature accumulates in the furnace 1a, and from an outlet (not shown). It is designed to leak to the outside. Further, the detector 10 is installed in a state of looking up at the blast furnace 1 from a position separated from the side surface of the bottom of the blast furnace 1.

In this embodiment, a nuclear emulsion plate is used as the detector 10. A nuclear emulsion is a type of film in which fine silver bromide crystals are uniformly dispersed in a gelatin film with a thickness of several tens of microns. When cosmic ray muons pass through the gelatin film, the trajectory is inside the gelatin film. It is supposed to be recorded in. Then, by reading the trajectory, the position where the cosmic ray muon has passed through the gelatin film and the direction in which the cosmic ray muon has passed can be detected.

In the example shown in FIG. 1 (b), the cosmic ray muon passes from the direction indicated by the broken line arrow at the point P1 on the detection surface 10a of the detector 10. As shown in the figure, if the z-axis is taken from the point P1 in the normal direction of the detection surface 10a, the x-axis is set horizontally on the detection surface 10a, and the y-axis is set perpendicular to the x-axis and the z-axis. The directions in which the muon passed the P1 point are the angle θ1 around the y-axis with respect to the z-axis (hereinafter, the angle around the y-axis with respect to the z-axis is referred to as “Yaw angle” θ) and the angle φ1 around the x-axis (hereinafter referred to as “yaw angle” θ). Then, the angle around the x-axis with respect to the z-axis can be expressed by using (referred to as "elevation angle" φ). At point P2, cosmic ray muons pass from the direction indicated by the arrow of the one-point chain line. For this cosmic ray muon, the x-axis, y-axis, and z-axis can be set in the same way to obtain cosmic rays. It is possible to detect the weft angle θ2 and the elevation angle φ2, which represent the direction in which the muon has passed. Since the specific method for detecting the passing direction of the cosmic ray muon from the trajectory remaining on the nuclear emulsion is well known, the description thereof is omitted here. Further, the combination of the yaw angle and the elevation angle through which the cosmic ray muon has passed may be referred to as the "arrival angle" of the cosmic ray muon below.

In this way, for each of the trajectories of the cosmic ray muons detected by the detector 10, once the cosmic ray muons have passed through the cosmic ray muons and the elevation angles are obtained, this time, they are set for each predetermined cosmic ray muon. And total for each predetermined elevation angle. As a preparation for that, first, the angle range in the weapon angle direction that can be detected by the detector 10 is divided into predetermined weapon widths dθ, and the angle range in the elevation angle direction is divided into predetermined elevation angle widths dφ.

FIG. 2 conceptually shows how the angle range in the weapon direction that can be detected by the detector 10 is divided into predetermined weapon widths dθ, and the angle range in the elevation angle direction is divided into predetermined elevation widths dφ. It is an explanatory diagram. In this way, if the angle range that can be detected by the detector 10 is divided into a predetermined weapon width dθ and a predetermined elevation width dφ, the cosmic ray muon detected by the detector 10 will always be any of them. It will be classified into that square. Therefore, if the detector 10 is installed on the side of the blast furnace 1 in the state illustrated in FIG. 1 (a) and the results of detecting a large number of cosmic ray muons over several months are aggregated, FIG. It is possible to obtain a frequency distribution in which the detection frequency of cosmic ray muons is set for each of the squares shown in.

In this embodiment, a nuclear dry plate is used as the detector 10, but other methods can be used as long as the passing direction of the cosmic ray muon can be detected. However, if a nuclear emulsion is used, a power source is not required, so that cosmic ray muons can be stably detected for a long period of time, and the spatial resolution on the detection surface 10a is high, so that cosmic ray muons can be detected. Even if is detected at a high density, individual cosmic ray muons can be separated and the passing direction can be detected. Therefore, a sufficient number of cosmic ray muons can be accumulated by using a nuclear emulsion. In order to secure the detection accuracy required for the boundary position detection process of the present embodiment described later, a sufficient number of detection frequencies are required for each of the squares illustrated in FIG. 2, and for that purpose. , The detector 10 needs to detect a large number of cosmic ray muons. In this respect, the method using a nuclear emulsion as the detector 10 can stably detect cosmic ray muons over a long period of time and can record the detection results at high density. It can be said that it is particularly suitable for the boundary position detection process of the example.

B. Principle of detecting the boundary position between the furnace wall of the blast furnace and the inside of the furnace:
As described above, if the distribution of the detection frequency with respect to the arrival angle of the cosmic ray muon is known, the boundary position between the furnace wall 1b and the inside 1a inside the blast furnace 1 can be detected. This is based on the following principle.

For example, in FIG. 2A, attention is paid to the detection frequency in the range surrounded by the broken line rectangle. These detection frequencies are the detection frequencies obtained when the elevation angle is φ1, although the weft angle θ is different. Here, since information such as the shape and dimensions of the blast furnace 1, the distance L from the blast furnace 1 to the detector 10, and the installation angle of the detector 10 with respect to the blast furnace 1 can be examined in advance, the elevation angle from the detector 10 can be determined. The plane that crosses the blast furnace 1 at φ1 can be easily determined. Furthermore, once the plane is determined, the path of cosmic ray muons coming from each angle θ can also be determined.

FIG. 3 is an explanatory diagram illustrating the path of cosmic ray muons that have come to the detector 10 from directions having an elevation angle of φ1 and a weft angle θ of different directions. Since the shape and dimensions of the blast furnace 1, the distance L from the blast furnace 1 to the detector 10, the installation angle of the detector 10 with respect to the blast furnace 1, and the like are known, the plane at which the elevation angle from the detector 10 is φ1 and crosses the blast furnace 1 is The plane DP shown by the alternate long and short dash line in FIG. 3 (a) can be determined, and when the cross section of the blast furnace 1 is taken in this plane DP, FIG. 3 (b) is obtained. Then, if the yaw angle θ with respect to the detector 10 is determined on this cross section, the cosmic ray muon path corresponding to the yaw angle θ is determined, for example, as shown by the broken line in the figure, the path A to the path F. Can be done. The shaded portion in the drawing is the furnace wall 1b of the blast furnace 1, and the inside of the furnace wall 1b is the inside of the furnace 1a. Normally, the inside of the furnace 1a is filled with pig iron.

In the routes A to F illustrated in FIG. 3 (b), the routes A to C pass through the portion of the furnace wall 1b and the portion of the furnace interior 1a, but the routes D and E are the same. The portion of the furnace wall 1b passes through, but the portion of the inside of the furnace 1a does not pass through. Further, regarding the route F, neither the portion of the furnace wall 1b nor the portion of the inside of the furnace 1a has passed. Further, the length of passing through the furnace wall 1b and the length of passing through the inside of the furnace 1a are different between the respective routes. In this way, when the weft angle θ changes, the length of passage through the furnace wall 1b and the inside of the furnace 1a changes. In FIG. 3B, the case where the weft angle θ takes a positive value is displayed, but the same applies to the case where the weft angle θ takes a negative value. Therefore, in order to avoid complicating the explanation, the case where the weft angle θ takes a positive value will be described below.

FIG. 4 is an explanatory diagram of the results of comparing the lengths of the passages A to F passing through the furnace wall 1b and the inside of the furnace 1a. First, when the whole is viewed as the blast furnace 1 without distinguishing between the furnace wall 1b and the inside of the furnace 1a, the length passing through the blast furnace 1 becomes shorter from the path A to the path F as the angle θ becomes larger. It has become. Next, when the furnace wall 1b and the inside of the furnace 1a are distinguished from each other, as the angle of view θ increases from the path A to the path C, the length passing through the portion of the inside of the furnace 1a becomes shorter, and in the path D, the length passing through the portion of the furnace 1a becomes shorter. The length passing through the furnace 1a becomes 0. Further, as the yaw angle θ increases from the route D to the route E, the length passing through the portion of the furnace wall 1b becomes shorter, and in the route F, the length passing through the furnace wall 1b also becomes zero.

Here, it is known that the cosmic ray muon passing through a substance has a larger amount of attenuation as the mass of the passing substance increases. In a normal case, the portion 1a in the furnace is filled with pig iron, and the pig iron has a mass about twice to three times that of the refractory brick. The longest path A passing through the portion 1a has the largest amount of cosmic ray muon attenuation. Then, as the length of passage through the furnace 1a becomes shorter, the amount of attenuation decreases in the order of the route B and the route C. The amount of change in the amount of attenuation at this time depends on the mass of pig iron. Then, after the length of passage through the furnace wall 1a becomes 0, the amount of attenuation decreases as the length of passage through the portion of the furnace wall 1b becomes shorter toward the path D and the path E, and the furnace wall 1b is moved. The amount of attenuation is the smallest in the route F where the passing length is also 0. The amount of change in the amount of attenuation at this time depends on the mass of the refractory brick. As mentioned above, since there is a large mass difference between pig iron and refractory bricks, the region where the pig iron angle is small (pig iron part) is defined by the yo angle where the length passing through the furnace 1a (that is, the pig iron part) becomes 0. The way of changing the amount of attenuation becomes discontinuous between the region where the weight is passed through and the region where the angle of weft is large (the region where the pig iron portion is not passed). Then, such a change in the amount of attenuation appears in the detection frequency of cosmic ray muons.

FIG. 5 is an explanatory diagram conceptually showing how the amount of attenuation of cosmic ray muons changes according to the weft angle θ. Cosmic ray muons that fall on the ground are known to have an energy distribution as shown in FIG. Assuming that the attenuation amount of the path through which the cosmic ray muon passes through the blast furnace 1 is a, the cosmic ray muon whose energy is smaller than the attenuation amount a stops in the blast furnace 1. Therefore, the cosmic ray muon detected by the detector 10 through the path is a cosmic ray muon having an energy larger than the attenuation a (that is, the shaded portion in FIG. 6).

As is clear from FIG. 6, the number of cosmic ray muons detected by the detector 10 decreases monotonically as the amount of attenuation of the route increases. Then, as shown in FIG. 5, the attenuation amount of the cosmic ray muon changes according to the yaw angle θ, and the attenuation amount changes at the yaw angle corresponding to the boundary between the inside 1a of the blast furnace 1 and the furnace wall 1b. Since the method of is discontinuous, the method of changing the detection frequency of cosmic ray muons should also be discontinuous. That is, as shown in FIG. 2 (a) surrounded by a broken line rectangle, the detection frequencies of cosmic ray muons obtained at a certain elevation angle φ are arranged by taking the weft angle θ on the horizontal axis, which is illustrated in FIG. As described above, the way of changing the detection frequency should be discontinuous at the portion corresponding to the boundary between the inside 1a of the blast furnace 1 and the furnace wall 1b. Therefore, it is considered possible to detect the boundary position between the furnace interior 1a and the furnace wall 1b in the blast furnace 1 by detecting the weapon whose detection frequency changes discontinuously in this way. Be done. The above is the principle of detecting the boundary position between the furnace interior 1a and the furnace wall 1b in the blast furnace 1 based on the detection frequency of cosmic ray muons.

However, in reality, it has been difficult to accurately detect the boundary position between the furnace interior 1a and the furnace wall 1b by the above-mentioned method. This is due to the following circumstances. First, inside the blast furnace 1, the hot pig iron is eroding the refractory bricks while flowing, and the degree of erosion varies depending on the location. Therefore, the inner shape of the furnace wall 1b is no longer circular. Absent. Moreover, in the portion where the pig iron and the refractory brick are in contact with each other, the pig iron and the refractory brick are mixed. Therefore, as conceptually shown in FIG. 8, for the cosmic ray muon passing through the blast furnace 1, the inside of the blast furnace 1 is formed of refractory bricks from the portion of the furnace 1a in which pig iron is flowing. It is in a state of continuously changing to the portion of the furnace wall 1b. Therefore, the actual amount of attenuation does not change clearly between the inside of the furnace 1a and the furnace wall 1b as illustrated in FIG. In addition, there are statistical variations in the detection frequency values obtained for each arrival angle.

For these reasons, the actual detection frequency of cosmic ray muons is as illustrated in FIG. 9, and it becomes difficult to determine the boundary position between the furnace interior 1a and the furnace wall 1b. There is. Therefore, in order to accurately detect the boundary position between the furnace interior 1a and the furnace wall 1b in the blast furnace 1 even from the detection frequency as illustrated in FIG. 9, the following method has been developed.

C. Boundary position detection method of this embodiment:
10 and 11 are flowcharts of the boundary position detection process of this embodiment. This process is performed by a computer (not shown) that analyzes the nuclear emulsion of the detector 10. As shown in FIG. 10, in the boundary position detection process, first, one locus of cosmic ray muons recorded on the nuclear emulsion is selected (step S100). Then, by analyzing the image of the locus, the elevation angle φ and the weft angle θ when the cosmic ray muon reaches the detector 10 are detected (step S101). Since the methods for detecting the elevation angle φ and the weft angle θ are well known, the description thereof will be omitted here.

Then, the obtained elevation angle φ and the weave angle θ are quantized using a predetermined angle width dφ for the elevation angle and a predetermined angle width dθ for the weft angle, and the elevation angle φ and the weft angle θ after quantization are expressed. "1" is added to the detection frequency of the arrival angle (step S102). Subsequently, it is determined whether or not all the loci stored on the nuclear emulsion plate have been processed (step S103), and if unprocessed loci remain (step S103: no), the process returns to the beginning and a new one is created. After selecting one locus (step S100), a series of subsequent operations described above are executed.

When it was determined that all the trajectories on the nuclear emulsion were processed by repeating these operations (step S103: yes), this time, the elevation angle φ for detecting the boundary position was obtained at each weft angle θ. Acquire the detection frequency (step S104). As a result, as illustrated in FIG. 9, the detection frequency at each weft angle θ can be obtained. Although the range in which the weft angle θ takes a positive value is displayed in FIG. 9, the same result can be obtained for the range in which the weft angle θ takes a negative value.

As described above, it is difficult to immediately determine the boundary position between the furnace wall 1b of the blast furnace 1 and the inside of the furnace 1a from the detection frequency obtained in this way. Therefore, the position of the weft angle that is the outermost part of the furnace wall 1b is determined (step S105). Since the dimensional shape of the blast furnace 1, the distance L from the blast furnace 1 to the detector 10, the installation angle of the detector 10 with respect to the blast furnace 1, and the like are known, the position of the outermost weft angle of the furnace wall 1b can be easily determined. be able to. The outermost weft angle position of the furnace wall 1b corresponds to the "outermost reaching angle" in the present invention. Subsequently, a plurality of predetermined actual measurement values are acquired as the actual measurement values of the furnace wall portion from the outermost side of the furnace wall 1b toward the inside of the furnace 1a (step S106).

FIG. 12 is an explanatory diagram showing how the actual measurement value of the furnace wall portion is selected from the actual measurement values of the detection frequency. As described above, since the actual measurement value corresponding to the outermost part of the furnace wall 1b can be determined in advance, a plurality of predetermined actual measurement values including the actual measurement value are selected as the actual measurement values of the furnace wall portion. .. In the example shown in FIG. 12, since the predetermined plurality of pieces are set to four, the four actually measured values indicated by the black circles in the figure are the measured values of the furnace wall portion.

Here, the operation of selecting the measured value of the furnace wall portion will be supplementarily described. As described above with reference to FIG. 9, the measured value of the detection frequency obtained for each weft angle θ does not clearly show the boundary position between the portion 1a in the furnace of the blast furnace 1 and the portion 1b of the furnace wall. .. On the other hand, the position corresponding to the outermost part of the furnace wall 1b can be accurately determined. Therefore, it is guaranteed that some measured values from the outermost part of the furnace wall 1b toward the inside of the furnace 1a correspond to the part of the furnace wall 1b (not the part of the inside of the furnace 1a). You can think of it. The plurality of actual measurement values selected as the actual measurement values of the furnace wall portion are thus actual measurement values that can be considered to correspond to the portion of the furnace wall 1b. If the angle width dθ for quantizing the weft angle θ is set to a small value to some extent in step S102 of FIG. 10, even if the measured values of the detection frequencies vary, a plurality of predetermined values from the outermost side can be set. It can be considered that the measured value surely corresponds to the portion of the furnace wall 1b.

Further, the number of "predetermined plurality" (that is, the number selected as the actual measurement value of the furnace wall portion) is set according to the functional form of the prediction formula described later. In this embodiment, since a quadratic polynomial with the weft angle θ as a variable is used as the functional form of the prediction formula, a predetermined plurality of numbers are set to four. Of course, the number is not limited to four, and a larger number may be set. In general, the larger the number selected as the actual measurement value of the furnace wall portion, the more accurately the boundary position between the furnace wall 1b and the inside 1a in the blast furnace 1 can be detected. However, if a large number is selected unnecessarily, the actually measured value of the portion 1a in the furnace is also selected as the actually measured value of the furnace wall portion, and there is a possibility that the detection accuracy of the boundary position is lowered.

Therefore, in step S106 of FIG. 10, after selecting a plurality of predetermined actual measurement values including the outermost actual measurement value of the furnace wall 1b, whether or not the inner actual measurement value can also be selected as the actual measurement value of the furnace wall portion. It is desirable for humans to judge whether or not. That is, with respect to the measured value existing inside the automatically selected measured value of the furnace wall (measured value indicated by the black circle in FIG. 12), the change in the detection frequency with respect to the weft angle θ ensures that the furnace wall 1b If it can be determined that it corresponds to the part of, it is desirable to include the measured value in the measured value of the furnace wall and perform the following operations. By doing so, the number of the actual measurement values of the furnace wall part to be selected can be increased without selecting the actual measurement value of the portion of the furnace wall 1a as the actual measurement value of the furnace wall part. It is possible to improve the detection accuracy of the boundary position of.

After that, a prediction formula for predicting the detection frequency is determined from the weft angle θ by using the plurality of measured values of the furnace wall portion thus acquired (step S107). As a method for determining the prediction formula, a well-known method using the so-called least squares method can be used. As described above, in this embodiment, a quadratic polynomial with the weft angle θ as a variable is used as the functional form of the prediction formula. Therefore, the prediction formula can be determined if the measured values at at least three weft angles θ are obtained, and the prediction formula can be obtained including the least squares error if four or more measured values are obtained. it can. The functional form of the prediction formula is not limited to a quadratic polynomial with the weft angle θ as a variable. Since it is important to use an appropriate functional form in order to determine an accurate and predictable prediction formula with a small number of measured values, an appropriate functional form is selected by trial and error.

When the prediction formula for predicting the detection frequency is obtained with the weft angle θ as a variable, the least squares error obtained at that time is also stored (step S108). The least squares error is simply the average value of the deviations between all the measured values used to determine the prediction formula and the predicted values obtained by the prediction formula. In this embodiment, the least squares method is used to determine the prediction formula, and the prediction formula using a quadratic polynomial with the weft angle θ as a variable is determined using four actually measured values. The least squares error is also calculated when determining the equation. Therefore, in step S108, the obtained least squares error is stored. When the prediction formula is determined using a method other than the least squares method, the minimum square error is calculated using the measured value used for determining the prediction formula and the predicted value based on the obtained prediction formula. Remember.

Subsequently, the actually measured value one inside (in the direction of 1a in the furnace) from the actually measured value of the furnace wall portion is selected as the actually measured value for inspection (step S109 in FIG. 11). FIG. 13 is an explanatory diagram showing a state in which the actual inspection value is selected. The black circles in the figure represent the measured values of the furnace wall, and the thick solid curve represents the prediction formula obtained from the measured values of the furnace wall. In step S109 of FIG. 11, the actual measurement value p1 inside the actual measurement value of the furnace wall portion is selected as the inspection actual measurement value.

Then, after calculating the predicted value of the measured value p1 selected as the measured measurement value at the weapon θ1 using the prediction formula (step S110), the deviation between the measured measurement value and the predicted value is larger than the least squares error. It is determined whether or not it is large (step S111). As a result, when it is determined that the deviation is smaller than the least squares error (step S111: no), the actual measurement value one inside the actual measurement value of the inspection is selected as a new actual measurement value of the inspection (step S112). .. In the example shown in FIG. 13, it is determined that the deviation between the measured value p1 and the predicted value at the weapon θ1 is smaller than the least squares error, and the measured value p2, which is one inside the measured value p1, is set. Select as a new test measurement value.

After selecting a new inspection actual measurement value in this way (step S112), after calculating the predicted value of the inspection actual measurement value at the weapon angle (yaw angle θ2 for the actual measurement value p2) (step S110), the inspection actual measurement value and It is determined whether or not the deviation from the predicted value is larger than the least squares error (step S111). By repeating such an operation, an actually measured value such that the deviation between the actually measured inspection value and the predicted value becomes larger than the least squares error is selected, and it is determined as "yes" in step S111. become. In the example shown in FIG. 13, the actually measured value p2 corresponds to such an actually measured value.

After that, the youth angle corresponding to the measured value selected as the inspection measured value at the end (θ2 in the example shown in FIG. 13) and the youth angle corresponding to the measured value selected as the inspection measured value immediately before that (θ2). In the example shown in FIG. 13, after the angle between θ1) is determined as the boundary position between the furnace wall 1b of the blast furnace 1 and the inside of the furnace 1a (step S114), the boundary position detection process of this embodiment is completed. To do. FIG. 14 shows the boundary position thus detected.

In the boundary position detection method of the present embodiment described above, the cosmic ray muon passes through the furnace wall 1b of the blast furnace 1 from the measured values of the detection frequencies obtained for various weapons. However, a measured value (that is, a value mounted on the furnace wall) that is certain that the portion 1a in the furnace has not passed is selected. Then, a prediction formula is generated using those measured values. In this way, if the path of the cosmic ray muon is within the angle range that does not extend to the furnace 1a, it is possible to determine a prediction formula that can obtain a reasonable prediction value for the weapon angle. Conversely, the measured values that deviate from the prediction formula thus obtained indicate that a part of the path of the cosmic ray muon hangs in the furnace 1a. Therefore, if the boundary position is detected by the above-mentioned method, it is possible to accurately determine the boundary position between the furnace wall 1b and the furnace 1a in the blast furnace 1 even from the actually measured values as illustrated in FIG. Become.

In addition, the method of the present embodiment described above also has the following advantages. For example, in the above-described embodiment, the shape of the outer surface of the blast furnace 1 has been described as being conical. However, the actual outer surface of the blast furnace 1 is not always a simple conical shape, and may have a distorted shape. FIG. 15 shows a case where a part of the outer surface of the blast furnace 1 is bulged in some places. In such a case, due to the change in the weapon, the length of the path passing through the portion of the furnace wall 1b also becomes slightly different from the case where the outer surface of the blast furnace 1 has a simple conical shape, and as a result, The measured values of the detection frequency of cosmic ray muons are also different.

Alternatively, in the above-described embodiment, the detection frequency of cosmic ray muons has been described as being determined by the amount of attenuation of cosmic ray muons on the path. However, cosmic ray muons do not fly from all directions at an equal frequency. Therefore, the actually measured detection frequency is also affected by the difference in the frequency of cosmic ray muons coming in due to the difference in the angle of weft. On the other hand, in the method of the present embodiment described above, since a prediction formula can be obtained in a state in which these influences are also taken into consideration, the prediction formula can be obtained in the blast furnace 1 with sufficient accuracy without being aware of the influences of these disturbances. It is possible to determine the boundary position between the furnace wall 1b and the inside of the furnace 1a.

D. Modification example:
In the above-described embodiment, the detection frequency of cosmic ray muons obtained for each reaching angle (that is, quantized elevation angle and weft angle) is used as it is for the furnace wall 1b and the furnace 1a in the blast furnace 1. It was explained as determining the boundary position of. However, if necessary, the boundary position may be determined after correcting the measured value of the detection frequency obtained for the weapon.

For example, as shown in FIG. 16A, a protrusion 11 may be formed on a part of the outer surface of the blast furnace 1. Alternatively, as shown in FIG. 16B, an object having a large mass such as an iron column 12 may exist around the blast furnace 1. In such a case, the amount of attenuation of cosmic ray muons increases in the path of the protrusions 11 and the iron columns 12, so that the detection frequency actually measured at the corresponding weapon decreases.

Here, since the protrusion 11 and the iron pillar 12 exist outside the blast furnace 1, the position and size thereof can be easily measured, and the weapon affected by the protrusion 11 and the iron pillar 12 can also be determined. Furthermore, since the amount of increase (or decrease) in the amount of attenuation due to the presence of the protrusions 11 and the iron pillars 12 can be estimated, the detection frequency that would have been obtained if the protrusions 11 and the iron pillars 12 were not present can also be estimated. Can be estimated. Therefore, the detection frequency actually measured at the weapon affected by the protrusion 11 and the iron column 12 is corrected to the estimated detection frequency. FIG. 17 illustrates a state in which the actually measured value displayed by the white circle is corrected to the estimated value displayed by the black circle at the position of the weapon θa. After performing such a pretreatment, if the boundary position between the furnace wall 1b and the furnace 1a in the blast furnace 1 is determined by using the method of the present embodiment described above, the boundary position can be determined more accurately. It becomes possible to decide.

Although the present embodiment and the modified examples have been described above, the present invention is not limited to the above-mentioned examples and the modified examples, and can be carried out in various embodiments without departing from the gist thereof.

1 ... blast furnace, 1a ... inside the furnace, 1b ... furnace wall, 10 ... detector,
11 ... protrusions, 12 ... iron pillars.

Claims (5)

By detecting cosmic ray muons that have passed through the blast furnace formed of refractory bricks using a detector installed away from the outer surface of the blast furnace, the boundary position between the furnace wall of the blast furnace and the inside of the furnace is detected. It is a method of acquiring information in the blast furnace to acquire information about
A detection frequency acquisition step of acquiring the detection frequency of the cosmic ray muon that has passed through the blast furnace and reached the detector for each arrival angle of the cosmic ray muon with respect to the detector.
Among the plurality of arrival angles at which the measured values of the detection frequencies were obtained, the cosmic ray muon is a furnace at which the furnace wall of the blast furnace is permeated but the inside of the blast furnace is not permeated. A step of selecting at least a predetermined number of wall arrival angles and a furnace wall arrival angle selection step.
A prediction formula generation step of generating a prediction formula for predicting the detection frequency with respect to the arrival angle based on the actually measured values of the detection frequencies obtained at the plurality of furnace wall portion arrival angles.
Inside the blast furnace including a boundary position determining step of determining the boundary position between the furnace wall and the inside of the furnace based on the deviation between the predicted value obtained by the prediction formula and the actually measured value obtained for each arrival angle. Information acquisition method. The method for acquiring information in a blast furnace according to claim 1.
Prior to selecting the plurality of furnace wall portions, the cosmic ray muon touches the outermost part of the furnace wall based on the outer shape of the blast furnace and the positional relationship between the blast furnace and the detector. A step of determining the outermost arrival angle, which is the transparent arrival angle, is provided.
The furnace wall portion reaching angle selection step is a step of selecting the plurality of furnace wall portion reaching angles from the outermost reaching angle toward the inside of the furnace of the blast furnace. Acquisition method. The method for acquiring information in a blast furnace according to claim 1 or 2.
Prior to selecting the plurality of furnace wall portion reaching angles, the measured values obtained for each reaching angle are corrected based on the outer shape of the blast furnace or at least one of the structures adjacent to the blast furnace. A method for acquiring information in a blast furnace including an actual measurement value correction process. The method for acquiring information in a blast furnace according to claims 1 to 3.
The detection frequency acquisition step is a method for acquiring information in a blast furnace, which is a step of acquiring a detection frequency per unit solid angle in a direction corresponding to the arrival angle. The method for acquiring information in a blast furnace according to any one of claims 1 to 4.
The prediction formula generation step is a step of calculating and storing the least squares error with the measured value at the furnace wall reaching angle when generating the prediction formula.
The boundary position determining step is a step of determining the boundary position by comparing the deviation between the predicted value by the prediction formula and the actually measured value obtained for each arrival angle with the least squares error. Information acquisition method.

Images