Cement kiln burning zone temperature measurement

The formation of the most important cement mineral, C3S (alite) occurs in the burning zone, where the temperature is between 1300-1450°C. The stability of burning zone temperatures directly determines the quality of the clinker. To ensure stability of burning zone temperature and maintain clinker quality, accurate temperature monitoring is critical.

Ratio pyrometer with cooling options

Measuring temperature in this environment is complicated by dust and fumes in the field-of-view and often elevated ambient temperatures at the installation locale. To overcome this obstacle, a ratio (2-colour) pyrometer with cooling options can be used.

The Endurance 2-colour infrared (IR) pyrometer determines temperature from the ratio of the radiated energies in two separate wavelength bands (colours). 2-colour pyrometers measure closer to the highest temperature within the measured spot (spatial peak picking) and their measurement is not affected by dust and fumes in their field-of-view. These features make them ideal for burning zone temperature measurement. The pyrometer owes this flexibility to the two different wavelength filters placed one on top of the other. This ‘sandwiched detector’ includes a narrow band detector with spectral range from 0,95 to 1,1 μm and a wide band detector with spectral range from 0,75 to 1,1 μm. The temperature range of the Endurance 2-colour model used for burning zone temperature measurement is from 600-1800°C.

The pyrometer can be installed by mounting a sighting tube on the kiln door/hood, followed by the blast gate and thermo jacket assembly. The blast gate is equipped with a quartz window and metal shutter. The window protects the pyrometer from harsh environments, while the metal shutter is useful during maintenance. The blast gate can handle temperatures up to 870°C. The thermo jacket’s rugged cast aluminium housing completely encloses the pyrometer head and provides water and/or air-cooling, along with air purging in one unit. An Endurance pyrometer fitted with a thermo jacket can withstand ambient temperatures as high as 315°C.

Endurance 2-colour infrared pyrometers can also be installed on the kiln platform looking through the observation window. For this installation a blast gate and thermo jacket are not required. The pyrometer can be ordered with a factory fitted air purge and integrated water cooled housing. The air/water cooled housing allows the pyrometer to be used in ambient temperatures up to 120°C with air cooling and 175°C with water cooling.

Endurance software facilitates real-time burning zone temperature data monitoring with live video feed of the burning zone through the built-in video camera included with the sensor. This feature is very useful in the event of failure of the CCTV camera. The pyrometer communicates with the software over Ethernet. RS-485 communication between the sensor and software is also possible for pyrometer configuration and temperature data monitoring. All pyrometer parameters can be configured via the software. The video feed and temperature data can also be monitored on a web browser via the built-in http server without using the endurance software.

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