Enhancement of Phenol Oxidation in Supercritical Water-Oxygen Fluid with Addition of Methane

The paper presents the results of a study of co-oxidation of phenol and methane in a supercritical water-oxygen fluid at a pressure of 25 MPa, starting temperature of 773 K, and variation in the flow rate of the phenol solution (3–7 g/min), oxygen (1.66–3.33 g/min), and methane (0.18–0.54 g/min). The experiments were carried out with the use of a vertically arranged tubular reactor in two modes: mixing of CH₄ and O₂ in counter jets in an ascending co-current flow of the phenol solution, as well as mixing of CH₄ and O₂ streams and the phenol solution at the lower part of the reactor. Data on the composition of the oxidation products and time dependences of the temperature of thermocouples and the power of ohmic heaters have been obtained. It has been shown that in both oxidation modes, the addition of methane leads to a significant (by several orders of magnitude) decrease in the content of phenols in the water collected at the outlet of the reactor. Due to the lower residual content of phenol in the water at mixing of the streams of the reagents in the lower part of the reactor, this method can be considered as more effective in comparison with oxidation in counter jets of CH₄ and O₂.