Pathways and kinetics of partial oxidation of phenol in supercritical water

This study reports on the pathways and kinetics of individual gaseous species involved in the partial oxidation of phenol in supercritical water. The pathway is a combination of supercritical water oxidation (SCWO) and supercritical water gasification (SCWG) processes. A kinetic model that involves oxygen is proposed that fits the experimental data and accurately predicts the effects of the O/phenol ratio on the decomposition of phenol. Specifically, at lower O/Phenol ratios, the gasification of acids and the water gas shift reaction predominated, increasing the amount of H2 in the gaseous products. At higher O/Phenol ratios, on the other hand, the oxidation of acid intermediates and CO oxidation predominated, thereby increasing the amount of CO2, while H2 decreased.

► The pathways of partial oxidation of phenol for hydrogen were found. ► We model kinetics for these reactions. ► The kinetic model can well predict the yields of H2 CO and CO2. ► Instead of converting waste just into CO2 and H2O, partial oxidation for waste-to-energy applications is possible in mechanisms.