Glossary
Fouling
Tube fouling
Also known as boiler tube fouling, heat exchanger tube fouling.
Tube fouling is the umbrella term for deposit accumulation on the gas-side outer surface of boiler and heat-exchanger tubes — economisers, superheaters, reheaters, air heaters, HRSG harps, recovery-boiler banks. The specific deposit composition varies by application, but the operational consequences are common.
What tube fouling does
- Insulates the tube from the gas, reducing heat transfer
- Raises flue-gas-side pressure drop, derating the ID fan
- Bonds chemically with the tube surface, creating local corrosion sites
- Channels gas flow around blocked passages, leaving fouled tubes worse and unfouled tubes overworked
Cleaning toolkit
Sonic horns prevent the early consolidation phase of tube fouling. Steam sootblowers attack thicker deposits. Periodic offline water-washing or chemical cleaning addresses what neither can manage.
Related terms
Related terms
- Fouling (general)Fouling is the accumulation of unwanted deposits on process-equipment surfaces. The general umbrella term covering slagging, scaling, coking, sintering and many other specific mechanisms.
- 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.
- SuperheaterA superheater is a tube bank that raises steam temperature beyond the saturation point using flue-gas heat. Sticky alkali ash and slag deposits are the dominant fouling concerns.
- Heat-transfer surface foulingHeat-transfer surface fouling describes tube fouling from the economic-impact angle: thermal-resistance addition that reduces heat absorption and degrades plant heat rate.
- 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.