Glossary
Boilers
Tube erosion and tube wastage
Also known as tube erosion, tube wastage, fly-ash erosion.
Tube erosion (also tube wastage) is the gradual thinning of boiler tube walls by repeated mechanical impact from particulate or by steam-jet impingement. Continued erosion eventually thins the tube below its design pressure rating, triggering boiler tube failure (BTF).
Two main mechanisms
- Fly-ash erosion — abrasive ash particles continuously impact tube surfaces, particularly in high-velocity sections of the convective pass and economiser. Worst on units burning high-ash coals
- Sootblower erosion — steam jets from poorly-aligned IK or IR sootblowers directly impinge on adjacent tubes, thinning them at the impingement zone
Mitigation
- Flow-shielding (chord plates, dummy tubes)
- Ash-load reduction (selective fuel blending, pre-cyclone removal)
- Sootblower lance alignment audits and re-aiming
- Coatings (HVOF, thermal-spray) on the most exposed tubes
Sonic horns and erosion
Sonic horns contribute zero mechanical erosion because they apply no contact force and no high-velocity jet. Plants that have suffered repeated sootblower-erosion BTF often retrofit horns and reduce sootblower duty, slowing the erosion progression.
Related terms
Related terms
- BoilerA boiler is a vessel that converts fuel chemical energy into steam by heating water. Coal-fired, biomass, oil, gas and recovery boilers all foul; sonic horns clean heat-transfer surfaces.
- Boiler tube failureBoiler tube failures are the leading cause of forced outages on industrial boilers. Causes range from creep and erosion to corrosion and overheating; cleaning practices contribute to several.
- EconomiserAn economiser is the final tube bank in a boiler's convective pass that recovers heat from the flue gas by preheating feedwater. Ash bridging in the economiser is a routine cleaning challenge.
- Steam sootblowerA steam sootblower projects high-pressure steam jets onto boiler tube banks to dislodge soot and ash. Effective but causes documented tube erosion and consumes valuable boiler steam.
- Sonic hornA sonic horn is a pneumatically-driven low-frequency sound emitter (typically 60–400 Hz at 140–180 dB SPL) used to dislodge particulate fouling from boilers, ESPs, baghouses and process vessels.