SOLID-STATE PHASE STABILITIES OF RELEVANCE TO METAL DUSTING IN COAL GASIFIER ENVIRONMENTS

Thermochemical calculations involving some typical mixed-gas environme nts and temperatures of gasifiers were used to examine iron-based phas e stabilities to assess the potential for metal dusting in coal gasifi cation systems. The results indicated that Fe3C is only stable under c onditions when certain reactions are suppressed and that FeO and Fe0.8 77S tend to form instead of the carbide. Assuming Fe3C is a necessary step in the metal dusting of steels, there are therefore numerous coal gasification systems where this type of carbon-related degradation wi ll not occur, particularly under conditions associated with higher oxy gen and sulfur activities.