Authors: P. Gebski, E. Shameli & A. Sadri
Molten 2009 - Proceedings of the VIII International Conference on Molten Slags, Flux and Salts, January 18 - 21, 2009
Abstract
Operation of pyrometallurgical and iron making furnaces is greatly affected by the integrity
and thickness of their refractory lining. Hatch NDT Group uses three (3) innovative techniques
to evaluate refractory lining integrity and thickness in operating furnaces: Acousto Ultrasonic-
Echo (AU-E), Taphole Acoustic Monitoring (TAM), and Infrared (IR) thermography.
Acousto Ultrasonic-Echo (AU-E) was developed based on the stress wave reflection principles. The system corrects for effect of temperature on the refractory wave speeds to
compute accurate refractory thickness. The AU-E technique could also be applied to determine
position of lining delamination, cracks and other anomalies within the refractory
structure.
The Taphole Acoustic Monitoring (TAM) system was developed based on the acoustic
emission (AE) principles. The receiving transducers are installed on the inlet and outlet
cooling circuits of water cooled tapping blocks. Using the sound generated from flow of
molten metal in the taphole, the system is capable of continuously determining refractory
wear within the tapping channel. This 24/7 continuous monitoring system is also capable
of assisting the operators for better lancing/tapping/drilling practice as it could illustrate
the intensity of the hits on the inner refractory lining in the tapping block.
The infrared (IR) thermographic cameras are commonly used to determine “hot spots”
on the vessels where the refractory wear could be worse than the surrounding areas. In our
approach, the data from IR camera is used to accurately determine refractory thickness in
one layer refractory lined cylindrical vessels such as converters and reactors.
In this paper, we introduce the principal concepts of the above three (3) NDT techniques
and present case studies and examples to illustrate the accuracy and repeatability of the
measurements.
