Definition - What does Cold Corrosion mean?
Cold corrosion is a type of corrosion resulting from condensation of sulfuric acid on the liner walls and deteriorate the liner surface. It is mostly occurred in the engine cylinder and heat exchangers. This corrosion can be kept under control to certain degree by raising the temperature of cooling water . To identify the causes of cold corrosion, condition monitoring is essential. It helps lot to mitigate corrosion effects.
This unusual corrosion produces excessive wear of lining material. Since new engines should comply with new NOx regulations, this corrosion has become crucial to the engine manufacturers.
Corrosionpedia explains Cold Corrosion
Cold corrosion is an abnormal corrosion accompanied by a drop in engine temperature, which allows acid to build up on the cylinder liner. Exhaust systems suffer from cold corrosion due to acid formation from combustion process of the engine. It produces sulfuric acid which leads to excessive liner wear, requiring expensive replacement.
Cold corrosion is not only serious in the latest engine designs but also it has impacts on earlier engine designs modified for part-load or low-load operation. The design modifications included:
- Variable turbo charger nozzle rings fitted
- Engine tuning changes
- Turbocharger cut-out
- Exhaust gas bypass valve fitted
Modifications did not provide cure for this corrosion to the engine. Some become mildly corrosive and others also remain potential to affect seriously.
The engine cylinders, in most recent engine designs, must operate under higher pressures and lower operating temperatures. It creates enabling conditions allows water to condense on the cylinder liner walls and form sulfuric acid with combining products from combustion process of engine. This ultimately leads to cold corrosion.