In-Depth Analysis: Application of Thermal Cameras in Rotary Kiln Fault Diagnosis at Iron and Steel Plants

At an iron and steel plant, the rotary kiln is an important device for calcining pallets in the ironmaking process. The rotary kiln body is the part that is heated. The inner lining of the rotary kiln is refractory, and a steel plate is on the surface. During normal operation, the internal temperature is over 1200°C, and the burning zone temperature is 1300 to 1400°C. Non-stop temperature measurement and temperature trend analysis of the inner shell and outer shell of the rotary kiln by using thermal cameras are particularly important.


In-Depth Analysis Application of Thermal Cameras in Rotary Kiln Fault Diagnosis at Iron and Steel Plants


I. Pain Points in the Industry

The inner wall close to the rotary kiln head has the highest temperature in the rotary kiln. With the increasing time of rotary kiln operations, the inner lining will become thinner and even fall off due to the constant high temperature and friction of clinkers. Consequently, the pipe wall temperature changes drastically, and the temperature in the rotary kiln becomes unevenly distributed, hampering stable and reliable operations of rotary kilns. An overly high temperature will cause over-calcination and a low temperature will cause under-calcination. Therefore, a too high or low temperature will not produce ideal calcination results. Traditional manual inspection can hardly discover exceptional areas, and cannot enable effective safety control for rotary kilns. 


II. Main Applications of Thermal Cameras in Rotary Kilns

Temperature Monitoring of the Rotary Kiln Outer Wall

The rotary kiln is large and keeps rotating, causing difficulties in the manual inspection. Besides, single-point temperature measurement will cause detection omission, and faults cannot be promptly eliminated. Thermal cameras enable all-weather temperature monitoring, temperature trend analysis, and alarm prompt for the rotary kiln outer wall, to replace manual inspection. The thermal cameras effectively transmit images and temperature data to the control room in real-time, to prevent, handle, and trigger alarms for problems.


Depth Analysis Application of Thermal Cameras in Rotary Kiln Fault Diagnosis at Iron and Steel Plants

Analysis Application of Thermal Cameras in Rotary Kiln Fault Diagnosis at Iron and Steel Plants


The rotary kiln head sprays fuel into the kiln. The exhaust gas generated through combustion goes to the material and then is let out from the rotary kiln discharge head. The temperature gradually decreases from the rotary kiln head to the rotary kiln discharge head. The temperature at the quenching position of the rotary kiln head can reach 1400°C, but the temperature at the rotary kiln discharge head is only 500 to 800°C. Thermal cameras can monitor the operation status and temperature fields of the combustion in the rotary kiln in real-time, for real-time visual display of temperature and history temperature queries.


III. Unique Advantages of Thermal Cameras in Rotary Kiln Detection

1. Professional temperature measurement tools help freely select monitored areas and automatically obtain the highest temperature point for regular inspection. Thermal image comparison helps discover the damage in the kiln lining, and notify staff or link automation devices for control. 

2. The settings of temperature threshold, duration, and sampling interval are available to achieve data collection. Thermal cameras are used to measure the temperature field of the outer wall. Then, analysis is conducted for the linear relationship between the outer wall temperature and corrosion in the inner lining refractory, and the obtained relationship serves as the reference to making maintenance plans.

3. Thermal cameras feature flexible and convenient operations. Preliminary constructions such as fixed platform installation and cable layout are no longer needed, and the device maintenance cost is relatively low.

4. The secondary development pack SDK is provided for users' secondary development. 


IV. Recommended Models

Temperature Monitoring of the Rotary Kiln Outer Wall:

AT31F/AT61F Thermal Camera


Thermal Cameras in Rotary Kiln Fault Diagnosis at Iron and Steel Plants


  • Adjustable -20°C ~ +150°C and 0°C ~ +550°C measurement levels

  • ±2°C or ±2% measurement accuracy

I/O alarm output is supported and external level signals can trigger alarm output

GB28181 and ONVIF protocols are supported

PTZ can be controlled via the RS485 interface

Implement the online real-time monitoring of multiple devices and data collection when equipped with professional PC software

Provide Windows & Linux-based SDKs, supporting secondary development by users

AT31/AT61 Thermal Camera


Cameras in Rotary Kiln Fault Diagnosis at Iron and Steel Plants


Adjustable -20°C ~ +150°C and 0°C ~ +550°C measurement levels

±2°C or ±2% measurement accuracy

Multiple lenses are available to choose and electric focusing is supported

PoE power supply and easy wire routing;

GB28181 and ONVIF protocols are supported

PTZ can be controlled via the RS485 interface

Implement the online real-time monitoring of multiple devices and data collection when equipped with professional PC software

Provide Windows & Linux-based SDKs, supporting secondary development by users

Temperature Monitoring in the Kiln:

AT31U Thermal Camera




In Rotary Kiln Fault Diagnosis at Iron and Steel Plants


  • 0°C to 1500°C ultra-wide measurement range 

  • ±2°C or ±2% measurement accuracy

  • 50 Hz high frame frequency

  • Multiple measurement tools fixed at any point; full-screen high/low-temperature capture; temperature measurement at central point; line/area analysis tool; manual temperature range selection

  • Supporting SDK-based secondary development on Linux and Windows for facilitating the integrated development of customers

  • Supporting multiple protocols such as Onvif/GB 28181/ Modbus TCP to access the industry or IoT system (supporting transmission area temperature information)


V. System Software

With the InfiRay IRT-VMS industrial thermal temperature measurement and monitoring system, multiple devices can be networked to connect the software platform for image displaying. A maximum of 64 real-time images can be displayed for video preview, and palette selection, temperature measurement tool configuration, and alarm configuration are supported. The temperature data curve and report are automatically generated to effectively monitor the whole process in the rotary kiln.


Application of Thermal Cameras in Rotary Kiln Fault Diagnosis at Iron and Steel Plants

Of Thermal Cameras in Rotary Kiln Fault Diagnosis at Iron and Steel Plants


VI. How Can I Produce a Thermal Image of Premium Quality?

Please refer to the following suggestions for using a thermal camera to produce a high-quality thermal image of the rotary kiln:

Select thermal cameras with high thermal sensitivity for scenarios with a small regional temperature difference in the rotary kiln;

Select products or levels of proper measurement ranges according to the temperature and scenarios of the inner and outer walls on the rotary kiln;

The temperature is high in the operating environment of the devices in the rotary, and explosion-proof shells are needed to protect the lens. The water jacket can be installed or part of the temperature in the rotary can be exported;

Use automatic measurement first, and then enable the temperature width stretch function. Manually set the temperature width to the minimum and include the previously measured temperature range to enrich the image details.