---
title: "Chloride-induced corrosion"
description: "Chloride-induced corrosion is the accelerated tube-wall thinning caused by chlorine-rich deposits on the steam-side surfaces of WtE, biomass and waste-fired boilers. Chloride corrosion is the dominant tube-failure mechanism in WtE and a major maintenance cost driver."
canonical_url: "https://sylio.co/glossary/chloride-induced-corrosion"
last_updated: "2026-06-28T02:29:41.343Z"
---

**Chloride-induced corrosion** is the accelerated tube-wall thinning caused by chlorine-rich deposits on the steam-side surfaces of [WtE](/glossary/waste-to-energy), [biomass](/glossary/waste-to-energy) and waste-fired boilers. Chloride corrosion is the dominant tube-failure mechanism in WtE and a major maintenance cost driver.

## Mechanism

Chlorine in the fuel enters the gas phase as HCl and metal chlorides. Inside a thin deposit on the tube, chloride and metal-chloride species shuttle electrons between the gas atmosphere and the tube surface. The result is rapid metal loss far in excess of what the temperature alone would predict. The "active oxidation" mechanism describes one variant; chloride attack on the protective oxide scale describes another.

## Where it dominates

- WtE superheaters — design temperatures kept low (380–420 °C) specifically to limit chloride corrosion
- Straw-fired boilers — see [straw firing](/glossary/straw-agricultural-residue-firing)
- RDF / SRF boilers — variable but generally high
- Heavy-petroleum-fired boilers with chloride contamination

## Mitigation

- **Material selection** — Inconel-625 weld overlays, nickel-based alloys on the most-exposed tubes
- **Lower steam temperature** at the superheater outlet to keep tube-metal below the corrosion threshold
- **Fuel control** — limit chloride loading where the contract permits
- **Sonic horns** — preventing deposits from consolidating reduces the chloride concentration immediately adjacent to the tube surface, indirectly slowing corrosion

## Related terms

- [Waste-to-energy](/glossary/waste-to-energy)
- [Alkali metals in ash](/glossary/alkali-metals-in-ash)
- [Low-melt sticky ash](/glossary/low-melt-sticky-ash)
- [Cold-end corrosion / dew-point corrosion](/glossary/cold-end-corrosion-dew-point-corrosion)
- [Tube erosion / tube wastage](/glossary/tube-erosion-tube-wastage)