---
title: "Chill-and-blow"
description: "Chill-and-blow is the periodic thermal-shock cleaning campaign performed on kraft recovery-boiler superheaters when in-service cleaning is no longer sufficient. The boiler load is rapidly reduced; the superheater tubes cool quickly; the temperature differential between the cooled tubes and the consolidated deposit cracks the deposit; intense sootblowing then dislodges the cracked deposit."
canonical_url: "https://sylio.co/glossary/chill-and-blow"
last_updated: "2026-06-28T02:29:36.010Z"
---

**Chill-and-blow** is the periodic thermal-shock cleaning campaign performed on [kraft recovery-boiler](/glossary/recovery-boiler) [superheaters](/glossary/superheater) when in-service cleaning is no longer sufficient. The boiler load is rapidly reduced; the superheater tubes cool quickly; the temperature differential between the cooled tubes and the consolidated deposit cracks the deposit; intense [sootblowing](/glossary/sonic-sootblower) then dislodges the cracked deposit.

## Why it matters operationally

A chill-and-blow campaign typically interrupts the boiler at full load for several hours and may require a brief mill production cutback. Mills target intervals of 12–18 months between chill-and-blow events; each additional week of run time defers a chill event and improves the mill's bottom line.

## Continuous cleaning to extend the interval

[Sonic horns](/glossary/sonic-horn) and [infrasonic cleaners](/glossary/infrasonic-cleaner) installed on the superheater extend the chill-and-blow interval substantially by preventing deposits from consolidating to the point where chill-and-blow is required. This is the headline operating-cost argument for acoustic-cleaning installation on recovery boilers.

## Distinguishing from water wash

[Water wash](/glossary/water-wash-recovery-boiler) is the more aggressive offline cleaning during a full boiler shutdown, where high-pressure water removes baked-on deposits that even chill-and-blow could not address.

## Related terms

- [Recovery boiler](/glossary/recovery-boiler)
- [Superheater](/glossary/superheater)
- [Water wash (recovery boiler)](/glossary/water-wash-recovery-boiler)
- [Sonic horn](/glossary/sonic-horn)