Different Vanadium Compounds Ash Corrosion of Boilers Using Heavy Fuel Oil

Vanadate induced or accelerated corrosion is observed in fossil energy conversion systems. The combustion of poor quality fuel oils with high asphaltene mounts and other vanadium and sulfur rich-compounds produces ash deposits on components such as heat exchangers, boilers or turbine blades and vanes. Boiler steel tubes are reported to be highly sensitive to this kind of high temperature corrosion enhanced by liquid phase fuel oil ash deposits.

The mechanisms of hot corrosion by molten sulfate-vanadate deposits were investigated for low and medium chromium steels as well as aluminide coated steels with different ash deposits containing CaSO₄, Ca₃(PO₄)₂, NaCl, Na₂O and Na₂S0₄ their combinations with V₂0₅. All samples were exposed to the ash deposits at 600°C in laboratory air. The deposits and the exposed surfaces were characterized by XRD, SEM and EPMA.