Assessing degradation mechanisms in supercritical water oxidation systems

There is a need to destroy both military and civilian hazardous waste and an urgency, mandated by public concern over traditional waste handing methodologies, to identify safe and efficient alternative technologies. One very effective process for the destruction of such waste is supercritical water oxidation (SCWO). By capitalizing on the properties of water above its critical point, (374°C and 221 atm for pure water), this technology provides rapid and complete oxidation with high destruction efficiencies at typical operating temperatures. Nevertheless, corrosion of the materials of fabrication is a serious concern and the practicality of SCWO may be limited by the ability to control corrosion. This paper reviews the current literature and presents experimental results for a number of candidate materials of fabrication. Among the potential modes of degradation, stress corrosion cracking (SCC) appears to be the most likely to result in catastrophic failure of a system component.