Glossary
Boilers
Boiler tube failure
Also known as BTF, boiler tube failures, tube leak.
Boiler tube failure (BTF) is the leading cause of forced outages on industrial and utility boilers worldwide. A single tube leak in a high-pressure section requires immediate shutdown for safety and repair, with outage costs running into millions of dollars on a large utility unit.
Common BTF mechanisms
| Mechanism | Typical location |
|---|---|
| Long-term overheating / creep | Finishing superheater, reheater |
| Short-term overheating | Waterwall at burner clusters |
| Fly-ash erosion | Economiser, convective-pass tubes |
| Sootblower erosion | Tube banks near sootblower lances |
| Cold-end corrosion | Air heater, economiser cold end |
| Hydrogen damage | High-heat-flux waterwalls |
| Stress-corrosion cracking | Cycling units, austenitic superheaters |
Cleaning practices and BTF
Cleaning choices contribute directly to several BTF mechanisms:
- Steam sootblower erosion is a documented cause of premature tube failure where lance alignment is poor or sootblowers fire too often
- Water-cannon thermal shock can crack tubes at the impingement zone
- Sonic horns carry no documented BTF mechanism because they apply no contact force; this is a routinely-cited reason for their adoption as a complement to (or partial replacement of) steam sootblowing on fouling-prone surfaces
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.
- Tube erosion and tube wastageTube erosion is the gradual thinning of boiler tubes by fly-ash impact and sootblower steam jets. Both are documented mechanisms of boiler tube failure.
- Cold-end corrosion and dew-point corrosionCold-end corrosion is the attack on air-heater and economiser surfaces below the acid dew point, where SO3 condenses as sulphuric acid. The leading cold-end failure mechanism.
- 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.