Supercritical water oxidation technology

Supercritical water oxidation technology is the enhancement and improvement of wet air oxidation technology, which was successfully developed by the American MODAR company in 1982. Its principle is to use supercritical water as a medium to oxidize and decompose organic matter.

It is also based on water as the main liquid phase, oxygen in the air as an oxidizer, and reacts at high temperature and pressure. However, its improvement and improvement lies in the use of the properties of water in supercritical state, the dielectric constant of water is reduced to approximately that of organic matter and gas, so that gas and organic matter can be completely dissolved in water, the phase interface disappears, and a homogeneous oxidation system is formed, which eliminates the interphase mass transfer resistance existing in the wet oxidation process and improves the reaction rate. Because of the higher independent activity of the oxidation state free radicals in the homogeneous system, the oxidation degree also increases.

Supercritical water is a good solvent for organic matter and oxygen, organic matter in oxygen-rich supercritical water homogeneous oxidation, its reaction speed is very fast, at 400~600℃, a few seconds can destroy the structure of organic matter, the reaction is complete and thorough, so that organic carbon, hydrogen completely converted into CO2 and H2O.

Supercritical water oxidation technology has attracted more and more attention because of its rapid reaction and thorough oxidation. How to reduce the reaction temperature and pressure or shorten the reaction residence time by using catalysts is a research hotspot in this field. At present, most of the commonly used catalysts are used in wet catalytic oxidation process. It is difficult to find catalysts with broad spectrum catalytic performance for supercritical water oxidation technology.