Abstract
The inspection and condition monitoring of smelting furnaces present significant challenges due to high operating temperatures, limited accessibility, and complex refractory and cooling system architectures. This paper presents an integrated refractory corrosion sensing and characterization approach that combines Acousto Ultrasonic-Echo (AU-E) measurements with thermal analysis to improve the detection, interpretation, and quantification of furnace degradation.
AU-E provides sensitivity to material changes such as chemical degradation, cracking, thickness loss, and loss of mechanical integrity by analyzing broadband elastic wave propagation through multi-layer furnace structures. Thermal analysis leverages available furnace data, including lining thermocouples, cooling-system measurements (e.g., water temperature/flow, heat flux), and process data (e.g., bath level, temperature, and composition). Thermal interpretation includes both (i) trend-based characterization of normal and abnormal operating periods and (ii) physics-based modeling (including finite element and inverse heat-conduction approaches) to estimate wear and protective buildup evolution from boundary measurements.
Individually, each technique offers partial insight into furnace conditions. Thermal data may reveal altered heat transfer without uniquely identifying the location and mechanism of subsurface damage, while AU-E can detect internal deterioration without directly linking it to operational thermal behavior. Their integration enables cross-correlation of structural integrity with thermal response, enhances defect discrimination, and reduces uncertainty in condition assessment. Based on field implementations and case studies, the combined AU-E and thermal framework enables earlier identification of corrosion-related damage and thickness loss, improved localization of critical degradation zones, and more accurate evaluation of furnace lining conditions supporting advanced asset integrity management (AIM) decision-making in pyrometallurgical operations.