An Overview of the Chemical and Electrochemical Conditions That Exist in SCWO Systems

Abstract Super critical Water Oxidation (SCWO) is currently being developed as a means of destroying resilient, highly toxic waste, such as halogenated hydrocarbons (e.g., polychlorinated biphenyls, PCBs) and the hydrolysate from chemical agents. The advantages offered by SCWO over incineration, for example, include closed cycle operation and very high destruction efficiencies. The latter are achieved by employing very aggressive oxidizing conditions that are obtained by maintaining a high oxygen fugacity in the system and by operating at elevated temperatures (up to 650°C). These conditions are also extraordinarily corrosive towards common structural materials, such as nickel-base alloys and ceramics. This paper reviews some of the properties that define the corrosiveness of SCWO media towards common structural materials and identifies issues that must be resolved before this technology becomes a practical reality.