Key words: supercritical water, hazardous organic substances, kinetics and mechanism of oxidation, tubular reactors, corrosion
The studies aimed at the environmentally benign destruction of hazardous organic substances (OS) and wastes via their oxidation in supercritical water (SCW) are reviewed. The advantage of SCW application is the capability of complete and rapid oxidation of OS in closed systems. The rate of oxidation is determined by temperature, OS to SCW and oxidant ratios, bond strengths in molecules of OS, their solubility in SCW and decreased in a sequence of aliphatic > aromatic, heterocyclic > polycyclic aromatic substances. The main products of oxidation are CO2, H2O and N2; sulfur, phosphorus and halogens are converted into corresponding mineral acids. Still, there are several difficulties in practical implementation of particular processes on industrial scale and related to the achievement of acceptable endurance, sustained and accident- free operation of SCW oxidation units. Heterogeneous processes on reactor walls result in negative phenomena, such as corrosion of constructional materials, precipitation and deposition of salts, and, as consequence, in the varied with time on stream kinetics of the main and conjugated reactions.
doi:10.1134/S1990793112070044