Fuel Ash Corrosion
Definition - What does Fuel Ash Corrosion mean?
Fuel ash corrosion is a corrosion mechanism that occurs in diesel engines, gas turbines, furnaces as well as other machinery that comes in contact with hot gas that contains a particular type of contaminant.
At times, fuel contains sulfate or vanadium compounds that can generate compounds with low melting points during the process of combustion. The melted liquid salts are extremely corrosive for stainless steel as well as alloys.
Fuel ash corrosion is also known as high-temperature corrosion.
Corrosionpedia explains Fuel Ash Corrosion
Fuel ash corrosion causes thinning at the tube walls that eventually leads to rupture of the steel. The biggest loss of metal takes place throughout the interface between the portion of the tube covered with ash and the portion that is uncovered.
Correcting this problem depends on the severity and an approximation of the remaining tube’s lifespan should be done on a tube sample. Short-term corrective actions include the use of thicker tubes as well as coating or shielding the tubes with materials and thermal-sprayed coatings that are resistant to corrosion.
Furthermore, fuel ash corrosion can be corrected by using tubes made from high-grade alloy that reduces the corrosiveness of ash. It can also be prevented by changing or blending fuel sources which minimize the contaminants, and by operating under temperatures where fuel ash corrosion is less likely to occur.
Other measures include using additives in the fuel, which can enhance the slag’s melting point, limiting the possibility of having deposits sticking on metal surfaces.