Furnace and acid tower refractory lining integrity monitoring by acoustic techniques
Process vessels such as smelting furnaces and acid towers are lined by refractory bricks. Degradation of the refractory lining in smelting furnaces begins since the start of the operation. For acid towers, the failure of castable refractory or the mortar between the refractories can cause high concentration acid leaks. Eventually the lining degradation becomes crucial and requires replacement. Since shutdowns are prohibitively expensive, it is desirable to identify the damaged areas and schedule maintenance shutdowns at the optimal frequency to reduce the cost of repair and shutdown periods. For this reason, non-destructive testing (NDT) techniques are developed to determine the lining condition while the vessels are still on-line. In this paper, we discuss the application of discrete Acousto Ultrasonic-Echo (AU-E) measurements and real-time continuous Acoustic Emission (AE) monitoring for the determination of refractory lining integrity in smelting furnaces and acid towers.