Oxidation in supercritical water: Pathways, kinetics, and mechanisms

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:430522

Savage, P E; Martino, C J; Brock, E E; Mizan, T I ^[1]

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1. Univ. of Michigan, Ann Arbor, MI (United States)

Supercritical water oxidation (SCWO) is a technology for treating aqueous waste streams, so that they can be recycled as process streams, and for the destruction of organic wastes. The process operates above the critical point of water, which allows the organic-oxygen-water mixture to exist in a single fluid phase. This phase behavior ensures the absence of interphase transport limitations, and elevated temperatures ensure rapid oxidation rates. This paper outlines two approaches to obtain kinetics models for engineering purposes. One approach is to develop phenomenological models that correlate the results of kinetics experiments. A second approach is to develop fundamental, predictive, mechanism-based kinetics models. our approaches include experimental, modeling, and computational components. Substituted phenols and simpler compounds such as acetic acid and methanol are the compounds we have studied most extensively. We have developed global reaction rate laws for the oxidation of these compounds, and we have developed empirical kinetics models for the global reaction pathways. We are also correlating the SCWO kinetics exhibited by different phenolic compounds by employing structure-reactivity relations based on linear-free-energy relationships. Free-radical mechanisms have been postulated for the oxidation of these compounds, and these mechanisms used as the foundation for a quantitative kinetics model. Finally, we are conducting molecular dynamics simulations of supercritical water to obtain a more detailed molecular-level description of the structure and properties of water in its supercritical state. This paper describes our recent progress in each of these areas and shows how these complementary activities can be integrated to develop reliable kinetics models. 21 refs., 1 tab.

• OSTI ID: 430522
• Report Number(s): CONF-960730--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CHEMICAL REACTION KINETICS
DECONTAMINATION
ORGANIC COMPOUNDS
OXIDATION
SUPERCRITICAL STATE
WASTE WATER