Fundamental Kinetics and Mechanistic Pathways for Oxidation Reactions in Supercritical Water

Future long term space flights will require on-board water/waste recycling in a partially or fully enclosed life support system. Oxidation of the products of human metabolism in supercritical water has been shown to be an efficient way to accomplish this recycling. Fundamental understanding of the oxidation of compounds in supercritical water is essential for the design, development and operation of a supercritical water oxidation unit. Oxidation studies of methane up to 700°C have recently been completed and are presented in this paper. Experiments are currently being performed to determine reaction kinetic parameters for the oxidation of other model compounds in supercritical water such as ammonia, methanol, acetaldehyde, and mixtures of ammonia and co-oxidants. Theoretical studies of fundamental kinetics and mechanistic pathways in supercritical water oxidation are discussed.