Guided Wave Acoustic Monitoring of Corrosion in Recovery Boiler Tubing

摘要

Corrosion of tubing used in black-liquor recovery boilers is a major concern in all pulp and paper mills. Extensiverncorrosion in recovery boiler tubes can result in a significant safety and environmental hazard. Considerable plantrnresources are expended to inspect recovery boiler tubing. Currently, visual and ultrasonic inspections are primarilyrnused during the annual maintenance shutdown to monitor corrosion rates and cracking of tubing.rnThis Department of Energy, Office of Industrial Technologies project is developing guided acoustic waves for usernon recovery boiler tubing. The feature of this acoustic technique is its cost-effectiveness in inspecting long lengthsrnof tubes from a single inspection point. A piezoelectric or electromagnetic transducer induces guided waves into therntubes. The transducer detects fireside defects from the coldside or fireside of the tube. Cracking and thinning onrnrecovery boiler tubes have been detected with this technique in both laboratory and field applications. Thisrntechnique appears very promising for recovery boiler tube application, potentially expediting annual inspection ofrntube integrity.