JP7502582B2 - Evaluation method for evaluating wear of refractory bricks - Google Patents

Description

The present invention relates to a method for evaluating the amount of wear of refractory bricks lining the shell inside a kiln.

Traditionally, the method used to determine the wear condition of the firebricks on the inside surface of a rotary kiln involves workers entering the kiln shell and directly measuring the wear using measuring instruments such as scales.

In Patent Document 1, in an investigation of corrosion thinning of heat exchanger tubes installed in oil refineries, petrochemical plants, etc., some tubes are extracted, cut in half lengthwise to perform halving processing, and the inner surface and outer surface of the half tube exposed by the halving processing are scanned with a 3D scanner to calculate three-dimensional shape data, and the amount of thinning is calculated from the three-dimensional shape data.

In Patent Document 2, a laser beam is irradiated in the kiln shell, which has a refractory material on the inner diameter side, in the direction of the central axis of the kiln shell parallel to the kiln shell, and the distance from the laser beam to the refractory material is measured to measure the thickness of the refractory material.

In Patent Document 3, in order to measure the thickness of the fireproof coating inside the furnace body, a measuring device is attached to a movable cart, and the remaining thickness of the fireproof coating inside the furnace body is calculated from the amount of movement of the scattered laser light beam, and the remaining thickness is displayed in a distribution diagram using two-dimensional isobars.

JP 2020-003420 A JP 2005-195380 A Japanese Patent Application Publication No. H01-114705

However, the wear of the firebricks (hereafter simply referred to as bricks) inside the kiln shell is measured by workers using a scale or similar to measure only a portion of the bricks. As a result, the upper part and areas that are out of reach must be visually inspected to determine whether there are any abnormalities, and there is a risk that the evaluation will differ depending on the worker. As a result, it is not easy to determine the extent of brick replacement or to uniformly manage wear predictions.

Meanwhile, 3D laser scanners are used in infrastructure surveys to measure the inside of tunnels, road surfaces, and so on. 3D laser scanners can create 3D image data of the actual site using huge amounts of point cloud data, and based on that 3D image data, it is possible to measure dimensions, calculate volume, and even create 2D drawings. Other benefits include a significant reduction in the time and manpower required for on-site work, ensuring safety, eliminating measurement errors by workers, and making it possible to measure complex shapes.

In Patent Document 1, it is difficult to measure the thickness of the object to be measured if the object has a large structure or if it is not possible to extract a portion of it, such as in a rotary kiln. In addition, in Patent Documents 2 and 3, it is very time-consuming and laborious to measure the thickness of the refractory material at all points inside the kiln shell.

The present invention was made in light of these circumstances, and aims to provide an evaluation method that can grasp the amount of wear on the refractory bricks inside the kiln shell and enable appropriate management of the refractory bricks.

(1) In order to achieve the above object, the present invention has taken the following measures. That is, the evaluation method of the present invention is an evaluation method for evaluating the wear amount of the refractory bricks inside a kiln shell in which a plurality of refractory bricks are laid, and is characterized by including at least the steps of scanning a plurality of locations inside the kiln shell using a 3D laser scanner, creating 3D image data of the inside of the kiln shell from point cloud data obtained by the scanning, calculating the distance from the central axis of the kiln shell to the surface of the refractory brick based on the created 3D image data, and calculating the difference between the radius of the kiln shell measured in advance and the calculated distance from the central axis of the kiln shell to the surface of the refractory brick as the remaining thickness of the refractory brick. This makes it possible to grasp the wear state of the refractory bricks throughout the kiln shell.

(2) In addition, the evaluation method of the present invention is characterized in that the radius of the kiln shell is rotated from an initial position to a predetermined angle on a cross section perpendicular to the central axis of the kiln shell, and the remaining thickness of the firebrick is calculated using the radius of the kiln shell after the rotation and the distance from the central axis on the radius of the kiln shell after the rotation to the surface of the firebrick. This makes it possible to grasp the wear state of the firebrick more accurately.

(3) In addition, in the evaluation method of the present invention, when the radius of the kiln shell is rotated from the initial position to a predetermined angle on two cross sections perpendicular to the central axis of the kiln shell, an evaluation range is determined from four intersections between the radius and the inner circumference of the kiln shell before and after the rotation, and the minimum remaining thickness within the evaluation range is set as the remaining thickness of the evaluation range. This makes it possible to more accurately grasp the wear state of the firebrick. In the evaluation range, the distance between the two cross sections is preferably 1 cm or more and 10 cm or less. In addition, in the evaluation range, the rotation angle of the radius is preferably 3 degrees or less, and more preferably 1 degree or more and 3 degrees or less.

(4) In addition, in the evaluation method of the present invention, when the radius of the kiln shell is rotated from the initial position to a predetermined angle on two cross sections perpendicular to the central axis of the kiln shell, an evaluation range is determined from four intersections between the radius and the inner circumference of the kiln shell before and after the rotation, and the average value of the remaining thickness within the evaluation range is set as the remaining thickness of the evaluation range. This makes it possible to grasp the wear state of the firebrick more accurately. In the evaluation range, the distance between the two cross sections is preferably 1 cm or more and 10 cm or less. In addition, in the evaluation range, the rotation angle of the radius is preferably 3 degrees or less, and more preferably 1 degree or more and 3 degrees or less.

(5) The evaluation method of the present invention further includes a step of creating a development diagram showing the wear amount of each of the firebricks in two dimensions based on the coordinate values of each of the firebricks obtained from the point cloud data and the evaluation range, and the development diagram is color-coded according to the remaining thickness of each of the evaluation ranges. This makes it easy to understand the wear state and distribution of the firebricks, and also makes it easy to identify firebricks that need to be replaced.

(6) The evaluation method of the present invention is also characterized by further including a step of adding information to the development diagram that identifies an evaluation range in which the remaining thickness is equal to or less than a predetermined threshold. This makes it possible to uniformly manage the determination of the brick replacement range and the wear amount prediction.

(7) In addition, in the evaluation method of the present invention, the distance between the two cross sections perpendicular to the central axis of the kiln shell is 1 cm or more and 10 cm or less. This allows the remaining thickness of the surface of one firebrick to be expressed in multiple evaluation ranges, that is, multiple squares in the 3D contour diagram and the 2D contour diagram, making it possible to accurately grasp the wear state of each individual firebrick.

(8) In addition, in the evaluation method of the present invention, the predetermined angle is 3 degrees or less. This allows the remaining thickness of the surface of one firebrick to be expressed in multiple evaluation ranges, i.e., multiple squares in the 3D contour diagram and 2D contour diagram, making it possible to accurately grasp the wear state of each individual firebrick.

According to the present invention, 3D image data of the overall shape of the inside of the kiln shell can be created, and the remaining thickness of each refractory brick can be determined from the 3D image data. As a result, it becomes possible to uniformly manage the determination of the extent to which bricks need to be replaced and the prediction of wear amount.

FIG. 13 is a diagram showing scanning inside a kiln shell. FIG. 2 is a diagram showing a schematic of a kiln shell and 3D image data of the kiln shell. 11A to 11C are diagrams illustrating a process of adjusting the reference coordinates. FIG. 2 is a schematic diagram showing a cross section of a kiln shell taken along the central axis (Z-axis) direction. FIG. FIG. 3D contour diagram showing the remaining thickness of refractory bricks throughout the kiln shell. FIG. 1 is a schematic diagram showing a 3D contour diagram and a kiln expansion diagram obtained by expanding the 3D contour diagram. FIG. 2 is a diagram showing a portion of a kiln development. This is a kiln development (2D contour diagram) created from a 3D contour diagram. This is a kiln development diagram showing whether or not it can be replaced. FIG. 13 is a diagram showing a method for predicting the amount of wear (remaining thickness).

The inventors noticed that it was difficult to accurately grasp the wear state of the multiple refractory bricks lining the inside of a kiln shell, and discovered that it was possible to use a 3D laser scanner to create 3D image data of the shape of the entire inside of the kiln shell, and to grasp the remaining thickness of each refractory brick from the 3D image data, which led to the present invention.

That is, the evaluation method of the present invention is a method for evaluating the wear amount of the internal refractory bricks of a kiln shell in which multiple refractory bricks are laid, and is characterized by including at least the steps of scanning multiple locations inside the kiln shell using a 3D laser scanner, creating 3D image data of the inside of the kiln shell from point cloud data obtained by the scanning, calculating the distance from the central axis of the kiln shell to the surface of the refractory brick based on the created 3D image data, and calculating the difference between the radius of the kiln shell measured in advance and the calculated distance from the central axis of the kiln shell to the surface of the refractory brick as the remaining thickness of the refractory brick. As a result, the inventors have made it possible to grasp the remaining thickness of all refractory bricks in the kiln shell. Hereinafter, this embodiment will be described with reference to the drawings.

Cement is manufactured through a process in which the main raw materials such as limestone, clay, and silica are crushed, dried, and mixed to produce powdered raw materials; the firing process in which the powdered raw materials produced in the raw material and crushing process are heated to a specified temperature and fired, causing a chemical reaction to produce clinker, which is the basis of cement; and the finishing process in which gypsum is added to the clinker produced in the firing process and crushed into a fine powder.

In the firing process, clinker is produced in a cylindrical rotating kiln known as a rotary kiln. The inner circumference of the rotary kiln is tightly lined with firebricks, and is designed to withstand the high temperatures of the kiln. The lining firebricks are exposed to high temperatures during the firing process and wear down as they come into contact with the raw materials, so worn firebricks must be replaced periodically.

In this embodiment, a 3D laser scanner is used to create 3D image data of the inside of the rotary kiln, the remaining thickness of the firebricks is calculated, and the wear amount of the firebricks is evaluated. The method for evaluating the wear amount of the firebricks is described below.

(Method of evaluating wear amount)
[1. 3D laser scanner]
The 3D laser scanner used in this embodiment will be described. In this embodiment, a three-dimensional measuring device manufactured by FARO is used as the 3D laser scanner. The measurement method of the 3D laser scanner adopts a non-contact method, and the measurement principle by the 3D scanner uses a phase difference method. The phase difference method is a method in which a laser light is irradiated to a measurement object, and the distance to the measurement object is measured by the phase difference between the emitted wave and the reflected wave of the laser light, and three-dimensional coordinates on the measurement object can be obtained. In addition, the 3D laser scanner used in this embodiment has a structure in which the measurement unit rotates vertically 360 degrees and the entire main body rotates horizontally 180 degrees. In this way, since the entire main body rotates horizontally 180 degrees while rotating the measurement unit 360 degrees, it is possible to obtain highly accurate data in a short time. Specifically, it is possible to measure the coordinates of 40 million points/3 minutes.

[2. Measurement of wear amount of refractory brick]
(1) Scanning by 3D laser scanner FIG. 1 is a diagram showing a state where the inside of a kiln shell is scanned by a 3D laser scanner. First, as shown in FIG. 1, in order to measure the amount of wear of the refractory bricks, the inside of a kiln shell 100 is scanned by a 3D laser scanner 11. The kiln shell 100, which is the object to be measured, is a cylindrical kiln shell lined with refractory bricks. The total length of the kiln shell 100 is 54 m, and the radius (design value) of the kiln shell 100 is 3.5 m. In addition, the size of one of the refractory bricks lined with the inside (before wear) is 10 cm long x 20 cm wide x 20 cm high.

Measurements are performed using the above-mentioned 3D laser scanner 11 (manufactured by FARO) with a scan speed of approximately 120,000 points/sec, accuracy of ±2 mm (range up to 130 m), and a measurement pitch of 6.3 mm at a distance of 10 m. Since the radius of the kiln shell is the reference surface (hereinafter also simply referred to as the reference surface) for calculating the amount of brick wear, measurements are also performed at points where the inner wall of the kiln shell 100 is exposed. Note that the design value may be used for the radius of the kiln shell 100.

The measurement interval is 10 m, and multiple reference balls 13 randomly placed inside the kiln shell 100 are used as markers to synthesize multiple point cloud data obtained from each measurement. By placing markers such as the reference balls 13 in this way, it becomes easier to stitch together each image (point cloud data).

When the number of points in the point cloud data obtained is 10 or more per brick, the point cloud will not be aligned due to the irradiation angle or the unevenness of the object, so the equipment is set up so that the number of measurement data points is appropriate. In addition, for the kiln shell 100, which is the object to be measured in this embodiment, the measurement pitch at a distance of 10 m is preferably 5 to 15 mm, and more preferably about 12 mm. The movement/installation interval of the 3D laser scanner 11 is preferably 10 to 20 m, and more preferably 15 m.

Figure 2(a) is a schematic diagram of the kiln shell 100, which is the object to be measured. Figure 2(b) is a diagram showing a range of approximately 2.4 m long x 2.8 m wide of the 3D image data (point cloud data) obtained by measuring Figure 2(a) with a 3D laser scanner. As shown in Figure 2(b), the wear state of each refractory brick can be determined from the 3D image data (point cloud data). In this way, by scanning the inside of the kiln shell 100 with a 3D laser scanner, the shape and characteristics of the inside of the kiln shell 100 can be accurately obtained.

(2) Adjustment of the Reference Coordinates Next, using the three-dimensional coordinate data (hereinafter also referred to as 3D image data) of the kiln shell acquired by scanning, the reference coordinates of the 3D image data are adjusted so that the center of the cross section of the flange part of the kiln shell becomes the origin of the three-dimensional coordinates. The adjustment of the reference coordinates will be described below.

Figure 3 is a diagram showing the adjustment process of the reference coordinates. First, in the kiln shell 200 of the 3D image data acquired by scanning, the central axis of the kiln shell is set as the Z axis, and a cylinder with a diameter of the part where the refractory bricks are removed and the inner wall of the kiln shell is exposed (shell exposed part B in Figure 3 (a)) is extended in the Z axis direction (arrow in Figure 3 (a)), and a reference surface that serves as a reference when calculating the wear amount of the refractory bricks is created (Figure 3 (a)). Note that the reference surface with a remaining thickness of 0 mm can also be created using the design value of the radius of the kiln shell 100 instead of the value obtained by measurement (the diameter of the part where the refractory bricks are removed and the kiln shell 100 is exposed). In addition, the outside of the kiln shell 100 can be scanned with a 3D laser scanner, and the radius of the kiln shell 100 can be calculated using the point cloud data showing the shape of the outside and the thickness (design value) of the kiln shell 100, and the reference surface with a remaining thickness of 0 mm can be created.

Next, the point cloud data acquired by scanning is converted from Cartesian coordinates to cylindrical coordinates, with the center of the flange surface of the kiln shell 200 represented by the 3D image data as the origin of the three-dimensional coordinates (Figure 3(b)).

(3) Calculation of Remaining Thickness of Refractory Bricks Fig. 4 is a schematic diagram showing a cross section perpendicular to the central axis (Z-axis) of the kiln shell. If the radius of the kiln shell is r1 and the distance from the central axis to the surface 21 of the firebrick is r2, the remaining thickness of the firebrick can be calculated by r1-r2. In this way, by calculating the remaining thickness of each firebrick throughout the kiln shell, the wear state of the firebricks can be grasped. Specifically, for example, the remaining thickness of each firebrick throughout the kiln shell is calculated by calculations such as Calculation Examples 1 to 3.

(Calculation Example 1)
As shown in Fig. 4, on a cross section perpendicular to the central axis of the kiln shell 200 in the 3D image data, the radius of the kiln shell 200 in the 3D image data is rotated from the initial position by a predetermined angle (θ), and the remaining thickness of the firebrick is calculated using the radius (r1) of the kiln shell after rotation and the distance (r2) from the central axis on the same radius as the kiln shell after rotation to the firebrick surface 21. This operation is performed 360 degrees on the cross section, and similarly on cross sections at regular intervals (t) in the central axis direction. This makes it possible to grasp the remaining thickness of all the firebricks in the kiln shell.

(Calculation Example 2)
As shown in Figures 5(a) and 5(b), in the kiln shell 200 of the 3D image data, when the radius of the kiln shell 200 of the 3D image data is rotated from the initial position to a predetermined angle (θ) on two cross sections perpendicular to the central axis of the kiln shell 200, an evaluation range A is determined from four intersections between the radius of the kiln shell 200 of the 3D image data and the inner circumference of the kiln shell 200 of the 3D image data before and after the rotation, and the minimum remaining thickness within the evaluation range A is set as the remaining thickness of the evaluation range A. This operation is performed 360 degrees on the cross section, and is also performed on cross sections at a constant interval (t) in the central axis direction. The distance between the two cross sections is a constant interval (t) in the central axis direction. This makes it possible to grasp the remaining thickness of all refractory bricks in the kiln shell.

(Calculation Example 3)
5(a) and 5(b), in the kiln shell 200 of the 3D image data, when the radius of the kiln shell 200 of the 3D image data is rotated from the initial position to a predetermined angle (θ) on two cross sections perpendicular to the central axis of the kiln shell, an evaluation range A is determined from four intersections between the radius of the kiln shell 200 of the 3D image data and the inner circumference of the kiln shell 200 of the 3D image data before and after the rotation, and the average value of the remaining thickness within the evaluation range A is set as the remaining thickness of the evaluation range. This operation is performed 360 degrees on the cross section, and is also performed on cross sections at a constant interval (t) in the central axis direction. The distance between the two cross sections is a constant interval (t) in the central axis direction. This makes it possible to grasp the remaining thickness of all the refractory bricks in the kiln shell.

By using the methods of calculation examples 1 to 3, it is possible to accurately determine the remaining thickness of all refractory bricks in the kiln shell. In this embodiment, the calculations were performed with θ = 3 degrees and t = 5 cm.

(4) Creation of 3D contour diagram Figure 6 is a 3D contour diagram showing the remaining thickness of some of the refractory bricks in the kiln shell. Figure 6 is a 3D contour diagram created by calculating the remaining thickness of the refractory bricks at each angle of each cross section, as explained in (3), using the reference plane of the remaining thickness of 0 mm, and importing it into 3D image data. Note that Figure 6 shows a range of about 20 m out of the total length of the kiln shell, which is 54 m. In this way, by creating a 3D contour diagram showing the remaining thickness of the refractory bricks in the entire kiln shell, it becomes possible to easily grasp the wear amount of the refractory bricks in the entire kiln shell. As a result, the area in which the refractory bricks need to be replaced can be easily and uniformly determined.

The evaluation range determined by the predetermined angle (θ) and the fixed interval (t) in the central axis direction used when calculating the remaining thickness of the firebrick corresponds to one square on the 3D contour diagram. Since it is preferable to understand the wear state of each individual brick, it is necessary to set the angle (θ) so that the surface of one firebrick is represented by multiple squares on the 3D contour diagram (details will be described later). In this embodiment, due to the size of the kiln shell and the size of the firebrick, it is preferable for θ to be 3 degrees or less, and more preferably 1 degree or more and 3 degrees or less.

[3. Kiln expansion diagram]
Since a plurality of refractory bricks are laid inside the kiln shell, after calculating the remaining thickness of the refractory bricks, it is necessary to know which refractory bricks need to be replaced and the positions and number of the refractory bricks that need to be replaced. In this embodiment, a development (hereinafter referred to as a kiln development) obtained by developing a 3D contour diagram showing the remaining thickness of the refractory bricks in the entire kiln shell is used as a method for knowing the positions and number of the refractory bricks. The kiln development will be described below.

(1) Creation of a kiln development diagram Figures 7(a) and 7(b) are schematic diagrams showing a 3D contour diagram and a kiln development diagram obtained by developing the 3D contour diagram. Figures 8(a) and 8(b) are diagrams showing a part of the kiln development diagram. The kiln development diagram shown in Figure 7(b) can be created by developing the 3D contour diagram with the circumferential direction of the cross section perpendicular to the central axis as the vertical axis and the central axis direction as the horizontal axis, as shown in Figure 7(a). That is, the 3D contour diagram showing the remaining thickness of the refractory bricks in the entire kiln shell shown in Figure 6 is developed with the circumferential direction as the vertical axis and the central axis direction as the horizontal axis to create a kiln development diagram. Figure 8(b) is an enlarged view of the dotted-line enclosed portion X in Figure 8(a), and the remaining thickness of the refractory bricks calculated for each evaluation range divided into 3 degrees in the circumferential direction in the cross section at every certain interval (t = 5 cm) in the central axis direction is shown in a 2D contour diagram. The size of the refractory bricks in the kiln shell, which is the measurement target of this embodiment, corresponds to four squares in the 2D contour diagram shown in Fig. 8. In other words, it is possible to grasp the wear state of each brick from the 3D contour diagram and the 2D contour diagram created in this embodiment.

Figure 9 shows a kiln development (2D contour diagram) created from a 3D contour diagram. The size of one square in the 2D contour diagram shown in Figure 9 corresponds to the evaluation range divided into certain intervals in the 3D contour diagram, with θ (vertical) = 3 degrees and t (horizontal) = 5 cm (50 mm). As shown in Figure 9, by using the kiln development shown in a 2D contour diagram, it is possible to easily grasp the amount of wear of the refractory bricks throughout the kiln shell. In addition, since it is possible to grasp the wear state of each individual brick, it is possible to grasp the overall wear state, as well as the position and number of refractory bricks that need to be replaced.

[4. Criteria for replacing bricks]
As described above, the use of 3D contour diagrams and kiln development diagrams makes it possible to grasp the overall wear status and identify bricks that need replacing. In addition, a method is described here that enables unified management of the decision by workers of the extent to which bricks need to be replaced.

As a method of unifying the judgment criteria, there is a method of setting a threshold value for the remaining brick thickness in advance. For example, the threshold value for the remaining brick thickness to be replaced is set to 100 mm, and the squares on the kiln development diagram are displayed in different colors depending on whether the measured remaining brick thickness is above or below the threshold, making it possible to make an immediate judgment. Figure 10 is a kiln development diagram showing whether or not replacement is possible. For example, the squares showing bricks with a remaining thickness of 100 mm or more are displayed in white, and the squares showing bricks with a remaining thickness of less than 100 mm are displayed in black (Figure 10(a)). By displaying these in the kiln development diagram, it becomes possible to replace bricks based on unified judgment criteria (Figure 10(b)). In this embodiment, white and black are used, but other colors such as red and blue may be used, and it is more preferable to use complementary colors.

[5. Prediction of wear amount (remaining thickness)]
The rotary kiln is periodically shut down and inspected. The wear status of the firebricks inside the kiln shell is also monitored during shutdown and replaced. The remaining thickness of the firebricks is recorded each time using a 3D laser scanner or the like, and the wear progression of each brick can be understood. For example, as shown in FIG. 11, the wear amount of each brick in the next inspection can be predicted (FIG. 11(b)) from the results of the previous and previous inspections (FIG. 11(a)), making it possible to smoothly replace the bricks. Furthermore, by accumulating data on the inspection results, the tendency of wear progression can be understood, and as a result, it is possible to improve the prediction accuracy of the wear progression of the bricks and confirm the long-term soundness.

As explained above, 3D image data of the overall shape of the inside of the kiln shell can be created, and the remaining thickness of each refractory brick can be determined from the 3D image data. As a result, it becomes possible to uniformly manage the determination of the area to be replaced and the prediction of the amount of wear.

100 Kiln shell 200 Kiln shell of 3D image data 11 3D laser scanner 13 Reference ball 21 Refractory brick surface A Evaluation range B Shell part (reference surface)

Claims (6)

A method for evaluating the wear of refractory bricks in a kiln shell having a plurality of refractory bricks laid therein and identifying bricks that need to be replaced, comprising the steps of:
A step of randomly arranging a plurality of markers inside the kiln shell, and scanning a plurality of points inside the kiln shell using a 3D laser scanner to obtain a plurality of point cloud data ;
Using the landmarks, synthesizing each point cloud data obtained by the scanning to create 3D image data of the inside of the kiln shell;
Calculating a distance from a central axis of the kiln shell to a surface of the refractory brick based on the created 3D image data;
Calculating a difference between a radius of the kiln shell measured in advance and a distance from a central axis of the kiln shell to a surface of the refractory brick as a remaining thickness of the refractory brick;
A step of determining an evaluation range from four intersections between the radius and the inner circumference of the kiln shell before and after rotation when the radius of the kiln shell is rotated from an initial position to a predetermined angle on two cross sections perpendicular to the central axis of the kiln shell;
creating a development diagram showing a two-dimensional wear amount of each of the refractory bricks based on the coordinate values of each of the refractory bricks acquired from the point cloud data and the evaluation range;
and identifying the positions and number of bricks that need to be replaced because the remaining thickness is equal to or less than a predetermined threshold in the developed view ;
The evaluation method is characterized in that the minimum remaining thickness in the evaluation range is determined to be the remaining thickness in the evaluation range . A method for evaluating the wear of refractory bricks in a kiln shell having a plurality of refractory bricks laid therein and identifying bricks that need to be replaced, comprising the steps of:
A step of randomly arranging a plurality of markers inside the kiln shell, scanning a plurality of locations inside the kiln shell using a 3D laser scanner, and acquiring a plurality of point cloud data;
Using the landmarks, synthesize each point cloud data obtained by the scanning to create 3D image data of the inside of the kiln shell;
Calculating a distance from a central axis of the kiln shell to a surface of the refractory brick based on the created 3D image data;
Calculating a difference between a radius of the kiln shell measured in advance and a distance from a central axis of the kiln shell to a surface of the refractory brick as a remaining thickness of the refractory brick;
A step of determining an evaluation range from four intersections between the radius and the inner circumference of the kiln shell before and after rotation when the radius of the kiln shell is rotated from an initial position to a predetermined angle on two cross sections perpendicular to the central axis of the kiln shell;
creating a development diagram showing the wear amount of each of the refractory bricks in a two-dimensional manner based on the coordinate values of each of the refractory bricks acquired from the point cloud data and the evaluation range;
and identifying the positions and the number of bricks that need to be replaced because the remaining thickness is equal to or less than a predetermined threshold in the developed view;
The evaluation method is characterized in that the average value of the residual thickness within the evaluation range is set as the residual thickness within the evaluation range. 3. The evaluation method according to claim 1 , wherein the developed view is color-coded according to the remaining thickness of each of the evaluation ranges. The evaluation method according to any one of claims 1 to 3 , characterized in that the distance between two cross sections perpendicular to the central axis of the kiln shell is 1 cm or more and 10 cm or less. 5. The method according to claim 1, further comprising the steps of: rotating a radius of the kiln shell from an initial position to a predetermined angle on a cross section perpendicular to the central axis of the kiln shell; and calculating a remaining thickness of the firebrick using the radius of the kiln shell after the rotation and a distance from the central axis on the radius of the kiln shell after the rotation to a surface of the firebrick. 6. The evaluation method according to claim 1 , wherein the predetermined angle is 3 degrees or less.

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