Glossary
Alternative cleaning
Online and offline cleaning
Also known as online cleaning, offline cleaning, in-service cleaning.
Online cleaning happens during plant operation; offline cleaning requires shutdown. The choice between them is one of the central economic decisions in industrial maintenance because every offline cleaning campaign costs lost production.
Online cleaning toolkit
- Sonic horns
- Steam sootblowers (all types)
- Water cannons
- Detonation cleaning (limited)
- Shock-pulse generator (recovery-boiler)
Offline cleaning toolkit
- Hydroblasting
- Dry-ice blasting
- Manual lancing
- Water wash
- Explosive deslagging
- Chemical cleaning (water-side)
The economic logic
Online cleaning is always cheaper per cleaning event than offline cleaning, because no production is lost. The strategic role of sonic horns, steam sootblowers and water cannons is therefore to defer offline cleaning campaigns as long as possible — typically aiming for one offline campaign per planned outage cycle, with online cleaning carrying the load between.
Related terms
Related terms
- 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.
- 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.
- Water wash (recovery boiler)A water wash is the offline cleaning campaign performed during recovery-boiler shutdowns, using high-pressure water to remove deposits that in-service cleaning cannot reach.
- Dry-ice blastingDry-ice blasting projects solid CO2 pellets onto a surface; the pellets sublimate on impact, leaving only the dislodged material as secondary waste. Common for offline boiler cleaning.
- Hydroblasting (offline cleaning)Hydroblasting uses high-pressure water (typically 700–2,000 bar) to remove hardened deposits from boiler tubes and process equipment during planned outages.