A method and system for on-line detection of the thickness of the ringed material in a pelletizing rotary kiln

Abstract

This invention provides an online detection method and system for the thickness of ring-forming material in a pellet rotary kiln. The method includes the following steps: S1, fixing an infrared rangefinder and a protractor to a support component, and placing the support component at the kiln head inspection hole of the rotary kiln; S2, keeping the infrared rangefinder fixed, measuring the distance and angle of multiple calibration points in the kiln head lining area through the kiln head inspection hole, and calculating the reference distance based on the distance and angle of the multiple calibration points. The reference distance is the vertical distance from the infrared rangefinder to the kiln head lining surface; S3, aligning the laser of the infrared rangefinder with the target ring-forming area, measuring the actual distance from the infrared rangefinder to the target ring-forming area and the actual angle between the radial line of the target ring-forming area and the laser emission axis, and calculating the thickness of the ring-forming material at the target ring-forming area. This method allows for the inspection of the rotary kiln condition without shutting down the kiln, saving manpower and financial resources.

Description

Technical Field

[0001] This invention relates to the field of ironmaking production technology, and more particularly to an online detection method and system for the thickness of ring material in a pellet rotary kiln. Background Technology

[0002] The rotary kiln for iron ore pelletizing is the core roasting equipment in the production of iron ore oxide pellets, and its inner wall is usually lined with refractory materials. During the rotary kiln production process, due to the rough surface of the refractory material inside the kiln, and the tendency of pellet powder and low-melting-point substances to adhere at high temperatures, these adhered materials gradually accumulate on the surface of the refractory material as the kiln continues to rotate, forming a dense bonding layer along the circumference, known as ring material. Ring material formation significantly increases the self-weight and transmission load of the rotary kiln, leading to increased energy consumption. Uneven distribution of ring material can also cause stress imbalance in the kiln body, inducing kiln deformation. When the ring material grows to a certain size, local detachment can tear or even damage the refractory material, and in severe cases, cause a red-hot kiln accident, forcing the production line to shut down for maintenance. Therefore, real-time monitoring of the ring material thickness is of great significance for ensuring the safe and efficient operation of the rotary kiln for pelletizing.

[0003] Currently, some technologies have been developed to detect the thickness of rings in rotary kilns or the lining thickness of similar high-temperature containers. For example, one method involves creating blind holes in the kiln wall that do not penetrate the refractory layer, measuring the temperature at the bottom of the holes, the temperature of the flue gas inside the kiln, and the heat flux density, and then indirectly calculating the ring thickness based on a heat conduction model. Another method uses an infrared thermometer to continuously measure the surface temperature of the outer wall of the rotary kiln, and combines this with the heat conduction equations for multi-layer cylindrical walls and the thermal conductivity parameters of the refractory material and the rings to inversely calculate the thickness of the rings inside the kiln. Furthermore, in measuring the residual lining thickness of similar high-temperature containers such as molten steel ladles, there are schemes that utilize laser rangefinders and specific vents at the bottom of the container as positioning references for scanning measurements.

[0004] However, the aforementioned existing technologies still have significant drawbacks in practical applications. Indirect measurement methods based on heat conduction models rely on multiple variable parameters, such as thermal conductivity, heat flux density, and ambient temperature. These parameters are difficult to stabilize under fluctuating production conditions, leading to decreased model calculation accuracy and significant deviations between the measured results and the actual thickness. Furthermore, the temperature conduction process itself has a lag, failing to meet the requirements for online real-time detection. The open-hole temperature measurement method requires disrupting the original kiln structure, increasing construction difficulty and cost, and posing a potential threat to the integrity of the refractory material and the safety of the kiln. The extrapolation method based on the kiln's outer wall temperature is significantly affected by external environmental conditions such as wind speed and air temperature, requiring complex correction models and being extremely cumbersome to implement. For laser ranging methods, existing solutions require setting dedicated physical reference points or inserting specific structures on the measured container, which is difficult to achieve for pellet rotary kilns that are rotating at high speeds and have a high-temperature, high-dust internal environment, and cannot be directly applied. Therefore, developing a detection method that does not require damage to the kiln body, does not rely on complex heat conduction models, and can directly measure the thickness of the ring-forming material online using the existing conditions of the rotary kiln has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose an online detection method and system for the thickness of ring-forming material in a pellet rotary kiln, so as to solve the technical problems of inaccurate measurement results or difficulty in implementation of existing ring-forming material thickness detection schemes.

[0006] The technical means employed in this invention are as follows: An online detection method for the thickness of the ring-forming material in a pellet rotary kiln includes the following steps: S1. Fix the infrared rangefinder and protractor to the support component, align the measuring baseline of the protractor with the laser emission axis of the infrared rangefinder, and place the support component at the kiln head inspection hole of the rotary kiln. S2. Keep the infrared rangefinder fixed and measure the distance and angle of multiple calibration points in the kiln head lining area through the kiln head inspection hole. The distance of each calibration point is the straight-line distance from the infrared rangefinder to the calibration point, and the angle of each calibration point is the angle between the radial line where the calibration point is located and the laser emission axis. Calculate the reference distance based on the distance and angle of multiple calibration points. The reference distance is the vertical distance from the infrared rangefinder to the surface of the kiln head lining. S3. Align the laser of the infrared rangefinder with the target ring area, measure the actual distance from the infrared rangefinder to the target ring area and the actual angle between the radial line of the target ring area and the laser emission axis, and calculate the thickness of the ring material at the target ring area using the reference distance, the actual distance and the actual angle.

[0007] Furthermore, in S2, the reference distance The calculation formula is as follows:

[0008] in, Where n is the distance between calibration points and n is the number of calibration points; The angle of the calibration point.

[0009] Furthermore, in S3, the formula for calculating the thickness of the ring-forming material is as follows:

[0010] in, This represents the actual distance from the infrared rangefinder to the target's ring-shaped area. The angle between the radial line where the target ring is located and the laser emission axis.

[0011] Furthermore, in S2, the selected multiple calibration points are located in an angle range of 5-15°, and the angle step between adjacent calibration points is 1°.

[0012] Furthermore, in S2, the distance data of each calibration point is measured no less than 3 times, and the arithmetic mean of the multiple measurement results is taken as the final distance of the calibration point.

[0013] Furthermore, it also includes S4: Keeping the tilt angle of the infrared rangefinder constant, S3 is executed repeatedly at preset time intervals to obtain thickness data of multiple ring-forming parts. The multiple thickness data are processed by interpolation to draw the outline of the ring-forming material in the circumferential direction of the rotary kiln.

[0014] Furthermore, the preset time interval is 10 seconds, and the interpolation method is any one of linear interpolation, polynomial interpolation, or spline interpolation.

[0015] Furthermore, the infrared rangefinder has a range of 0-40m, an accuracy of ≤5mm, a laser wavelength of 850nm-950nm, and a measurement response time of ≤10ms; the protractor has a range of 0-180° and an accuracy of ≤0.1°.

[0016] Furthermore, the supporting component is a tripod or a tray with a fixing clamp, and the infrared rangefinder and protractor are detachably fixed to the supporting component by bolts or buckles.

[0017] This invention also provides an online detection system for the thickness of ring-forming material in a pellet rotary kiln, for implementing the online detection method for the thickness of ring-forming material in a pellet rotary kiln as described in any one of the above claims, comprising: The ranging module uses an infrared rangefinder to measure the distance data from the infrared rangefinder to the surface of the kiln head lining or the surface of the ring formation area; The angle measurement module uses a protractor to measure the angle between the radial line where the calibration point or knot is located and the laser emission axis of the infrared rangefinder. The fixed module includes a support body and a fixing structure. The support body is used to be mounted at the kiln head inspection hole, and the fixing structure is used to fix the distance measuring module and the angle measuring module to the support body, and to make the measurement reference of the two coaxial. The data processing module communicates with the ranging module and the angle measurement module to receive distance and angle data, perform baseline distance calculation and ring material thickness calculation, and output the ring material thickness at the target ring location.

[0018] Compared with the prior art, the present invention has the following advantages: This invention eliminates the need for drilling holes or installing sensors on the rotary kiln wall. It utilizes existing kiln head inspection holes for measurement without damaging the kiln structure or refractory material layer. It can perform real-time detection under normal rotary kiln production conditions, avoiding safety hazards and kiln shutdown losses caused by drilling holes.

[0019] This invention employs a geometric method combining infrared ranging and angle measurement. It only requires two parameters, distance and angle, to calculate the thickness of the ring material using trigonometric functions. It eliminates the need to measure variable parameters such as flue gas temperature and heat flux density, and also eliminates the need to establish complex heat transfer equations. The calculation is fast and accurate, and is unaffected by fluctuations in production conditions.

[0020] This invention establishes a virtual reference distance by measuring multiple calibration points in the kiln head lining area, replacing the traditional method that relies on a specific physical structure as a positioning reference. This solves the technical problem of the pellet rotary kiln not having a fixed reference and being in a rotating state, while also eliminating the influence of equipment installation errors and irregular kiln lining. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram illustrating the principle of the present invention.

[0023] Figure 2 This is a diagram showing the outline of the knot in an embodiment of the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] This invention provides an online detection method for the thickness of the ring-forming material in a pellet rotary kiln, comprising the following steps: S1. Fix the infrared rangefinder and protractor to the support component, align the measuring baseline of the protractor with the laser emission axis of the infrared rangefinder, and place the support component at the kiln head inspection hole of the rotary kiln. Select an infrared rangefinder with a range of 0-40m and an accuracy of ≤5mm, a protractor with a range of 0-180° and an accuracy of ≤0.1°, and a support component for fixing the infrared rangefinder and the protractor; fix the infrared rangefinder and the protractor on the support component, with the test section located at the inspection hole at the kiln head of the rotary kiln; The supporting component is a tripod or a tray with a fixing clamp. The infrared rangefinder and protractor are detachably fixed to the supporting component by bolts or buckles, and the measuring baseline of the protractor coincides with the laser emission axis of the infrared rangefinder.

[0027] The distance to each calibration point shall be measured no less than three times, and the arithmetic mean of the multiple measurements shall be taken as the final distance of that calibration point. The reference distance is... This represents the average or median of the final distances for all calibration points.

[0028] S2. Keep the infrared rangefinder fixed and measure the distance and angle of multiple calibration points in the kiln head lining area through the kiln head inspection hole. The distance of each calibration point is the straight-line distance from the infrared rangefinder to the calibration point, and the angle of each calibration point is the angle between the radial line where the calibration point is located and the laser emission axis. Calculate the reference distance based on the distance and angle of multiple calibration points. The reference distance is the vertical distance from the infrared rangefinder to the surface of the kiln head lining. With the rangefinder fixed in place, measure the distance from the calibration point to the origin O within a range of 5-15° (1° increment) through the kiln head inspection hole. (n=1,2,3...11) and the angle between the calibration point and the radial line Then take the mean of the measured data and calculate the mean at this time. ,Right now

[0029] The distance to each calibration point shall be measured no less than three times, and the arithmetic mean of the multiple measurements shall be taken as the final distance of that calibration point. The reference distance is... This represents the average or median of the final distances for all calibration points.

[0030] S3. Align the laser of the infrared rangefinder with the target ring area, measure the actual distance from the infrared rangefinder to the target ring area and the actual angle between the radial line of the target ring area and the laser emission axis, and calculate the thickness of the ring material at the target ring area using the reference distance, the actual distance and the actual angle.

[0031] Based on the obtained baseline distance Based on this, the laser rangefinder is aimed at the target area to obtain the distance from the test area to the test origin O. The angle between the calibration point and the radial line The thickness of the ring material at this test location for:

[0032] S4. Keep the test tilt angle unchanged, repeat S3 every 10 seconds to measure the thickness. Use interpolation to process the thickness data from multiple measurements and draw the outline of the ring material in the circumferential direction of the rotary kiln.

[0033] The interpolation method can be linear interpolation, polynomial interpolation, or spline interpolation. The outline of the ring material is drawn with the circumferential angle of the rotary kiln as the horizontal axis and the thickness of the ring material as the vertical axis.

[0034] This invention also provides an online detection system for the thickness of ring-forming material in a pellet rotary kiln, for realizing the above-mentioned online detection method for the thickness of ring-forming material in a pellet rotary kiln, comprising: The ranging module uses an infrared rangefinder to measure the distance data from the infrared rangefinder to the surface of the kiln head lining or the surface of the ring formation area; The angle measurement module uses a protractor to measure the angle between the radial line where the calibration point or knot is located and the laser emission axis of the infrared rangefinder. The fixing module includes a support body and a fixing structure. The support body is used to be mounted at the kiln head inspection hole, and the fixing structure is used to fix the distance measuring module and the angle measuring module to the support body, and to make their measurement references coaxial. The fixing structure includes an adjusting bracket and a locking component. The adjusting bracket can be adjusted up and down along the height direction of the support body, and the locking component is a bolt or a quick-release buckle, used to fix the relative position of the distance measuring module and the angle measuring module.

[0035] The data processing module communicates with the ranging module and the angle measurement module to receive distance and angle data, perform baseline distance calculation and ring material thickness calculation, and output the ring material thickness at the target ring location.

[0036] The data processing module is a microcontroller, PLC, or industrial computer, and the display module is an LCD screen or touch screen. The data processing module transmits data with the ranging module and the angle measuring module through wired or wireless communication.

[0037] Display module: Used to display the measured tilt angle, distance, ring material thickness data and the drawn ring outline diagram in real time.

[0038] It also includes a data storage module, which is connected to the data processing module and is used to store all raw measurement data, calculation results and drawn contour map data, in CSV, Excel or image format.

[0039] like Figure 1 As shown, this method uses the principle of infrared ranging, employing an infrared rangefinder with a range of 0-40m to calculate the thickness of the ring-forming material in the rotary kiln based on angle and distance. The basic principle is as follows:

[0040]

[0041] in, The angle of inclination of the test area; The thickness of the ring material in the rotary kiln at the test location is shown in mm. The distance from the kiln head rangefinder to the rotary kiln lining is in mm. The distance from the knotted part to the rangefinder is in mm.

[0042] Example Measurement of the thickness of the ring material in a rotary kiln for coal-based pelletizing, Φ4.5m×40m chain grate machine - rotary kiln coal-based pelletizing production line.

[0043] This embodiment focuses on a coal-based rotary kiln for pelletizing, using pulverized coal as fuel. The kiln is hot and dusty, with rings mainly distributed in the radial region of the kiln head at 10°-15°. The specific steps for measuring the thickness of the ring material are as follows: S1. Equipment Selection and Installation: Select an infrared rangefinder with a range of 0-40m and an accuracy of ±5mm. The infrared rangefinder has a laser wavelength of 905nm and a response time of 8ms. It is equipped with an electronic digital protractor with a range of 0-180° and an accuracy of 0.1°. The support component is a high-temperature resistant tripod. The infrared rangefinder and protractor are detachably fixed to the tripod with bolts. The measurement baseline of the protractor is aligned with the laser emission axis of the rangefinder. The equipment is set up 0.7m in front of the kiln head inspection hole, and the test position is directly facing the kiln head lining area. The equipment is then fixed and calibrated.

[0044] S2. Reference Distance Measurement: Keeping the rangefinder fixed, select 11 calibration points within a range of 5-15° with a step size of 1° through the kiln head inspection hole. Measure each calibration point 4 times to eliminate dust interference inside the kiln. Take the arithmetic mean as the final distance from the calibration point to the origin O. Simultaneously record the angle between each calibration point and the radial line. After calculation, the final distances of the 11 calibration points are 2102mm, 2119mm…2221mm, as shown in Table 1. Take the average of all the final distances of the calibration points as the reference distance L0 = 2179mm.

[0045] Table 1. Calibration Point Values

[0046] S3. Calculation of ring material thickness: After obtaining the reference distance H0, the infrared rangefinder laser penetrates the dust inside the kiln and is aimed at the ring target part at the 87° radial angle of the kiln head. The actual distance L1 from the ring part to the origin O is measured to be 32283mm, and the angle α between the calibration point and the radial line is 87°. Substituting into the thickness calculation formula d = H0 - L1 × cosα, the thickness of the ring material is calculated to be d = 2179 - 32283 × cos87° ≈ 2179 - 1714 ≈ 464.4mm, which is rounded to 464mm according to the accuracy requirements.

[0047] S4. Ring Contour Drawing: Maintaining the test inclination angle at 87°, and considering the rotary kiln speed of 1.2 r / min for coal-based pellets, a thickness measurement was performed every 10 seconds, corresponding to a 12° rotation of the kiln body. This was repeated 30 times, covering the entire 360° circumference of the kiln, as shown in Table 2. Linear interpolation was used to complete the measurement gap data. The ring contour diagram was drawn with the rotary kiln circumferential angle as the abscissa and the ring material thickness as the ordinate, as shown in Table 2. Figure 2As shown in the figure. The results show that the ring thickness in the rotary kiln for coal-based pellets ranges from 82 to 108 mm, with the thickest ring on the discharge side of the kiln head, providing data support for subsequent ring cleaning operations.

[0048] Table 2 Thickness Measurement Table

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An online detection method for the thickness of the ring-forming material in a pellet rotary kiln, characterized in that, Includes the following steps: S1. Fix the infrared rangefinder and protractor to the support component, align the measuring baseline of the protractor with the laser emission axis of the infrared rangefinder, and place the support component at the kiln head inspection hole of the rotary kiln. S2. Keep the infrared rangefinder fixed and measure the distance and angle of multiple calibration points in the kiln head lining area through the kiln head inspection hole. The distance of each calibration point is the straight-line distance from the infrared rangefinder to the calibration point, and the angle of each calibration point is the angle between the radial line where the calibration point is located and the laser emission axis. Calculate the reference distance based on the distance and angle of multiple calibration points. The reference distance is the vertical distance from the infrared rangefinder to the surface of the kiln head lining. S3. Align the laser of the infrared rangefinder with the target ring area, measure the actual distance from the infrared rangefinder to the target ring area and the actual angle between the radial line of the target ring area and the laser emission axis, and calculate the thickness of the ring material at the target ring area using the reference distance, the actual distance and the actual angle.

2. The online detection method for the thickness of the ring-forming material in a pellet rotary kiln according to claim 1, characterized in that, In S2, the reference distance The calculation formula is as follows: in, Where n is the distance between calibration points and n is the number of calibration points; The angle of the calibration point.

3. The online detection method for the thickness of the ring-forming material in a pellet rotary kiln according to claim 2, characterized in that, In S3, the formula for calculating the thickness of the ring-forming material is as follows: in, This represents the actual distance from the infrared rangefinder to the target's ring-shaped area. The angle between the radial line where the target ring is located and the laser emission axis.

4. The online detection method for the thickness of the ring-forming material in a pellet rotary kiln according to claim 1, characterized in that, In S2, the selected calibration points are located in an angle range of 5-15°, and the angle step between adjacent calibration points is 1°.

5. The online detection method for the thickness of the ring-forming material in a pellet rotary kiln according to claim 1, characterized in that, In S2, the distance data of each calibration point is measured no less than 3 times, and the arithmetic mean of the multiple measurement results is taken as the final distance of the calibration point.

6. The online detection method for the thickness of the ring-forming material in a pellet rotary kiln according to claim 1, characterized in that, Also includes S4: Keeping the tilt angle of the infrared rangefinder constant, S3 is executed repeatedly at preset time intervals to obtain thickness data of multiple ring-forming parts. The multiple thickness data are processed by interpolation to draw the outline of the ring-forming material in the circumferential direction of the rotary kiln.

7. The online detection method for the thickness of the ring-forming material in a pellet rotary kiln according to claim 6, characterized in that, The preset time interval is 10 seconds, and the interpolation method is any one of linear interpolation, polynomial interpolation, or spline interpolation.

8. The online detection method for the thickness of the ring-forming material in a pellet rotary kiln according to claim 1, characterized in that, The infrared rangefinder has a range of 0-40m, an accuracy of ≤5mm, a laser wavelength of 850nm-950nm, and a measurement response time of ≤10ms; the protractor has a range of 0-180° and an accuracy of ≤0.1°.

9. The online detection method for the thickness of the ring-forming material in a pellet rotary kiln according to claim 1, characterized in that, The supporting component is a tripod or a tray with a fixing clamp, and the infrared rangefinder and protractor are detachably fixed to the supporting component by bolts or buckles.

10. An online detection system for the thickness of ring-forming material in a pellet rotary kiln, used to implement the online detection method for the thickness of ring-forming material in a pellet rotary kiln as described in any one of claims 1-9, characterized in that, include: The ranging module uses an infrared rangefinder to measure the distance data from the infrared rangefinder to the surface of the kiln head lining or the surface of the ring formation area; The angle measurement module uses a protractor to measure the angle between the radial line where the calibration point or knot is located and the laser emission axis of the infrared rangefinder. The fixed module includes a support body and a fixing structure. The support body is used to be mounted at the kiln head inspection hole, and the fixing structure is used to fix the distance measuring module and the angle measuring module to the support body, and to make the measurement reference of the two coaxial. The data processing module communicates with the ranging module and the angle measurement module to receive distance and angle data, perform baseline distance calculation and ring material thickness calculation, and output the ring material thickness at the target ring location.

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