Mechanism of H2-O2 reaction in supercritical water

H-2-O-2 reaction in supercritical water has been widely studied due to its promising application in industry. The global rate of this reaction was found independent of O-2 with equivalence ratio ranging from 0.042 to 4.1 in the literature. Aim of current study is to examine intermediates interaction responsible for properties of the O-2 independence and others. The study involves experiment re-examining the oxygen independence phenomenon and simulation centering on reduced mechanisms derived by quasi-steady-state approximation. The experiment with equivalence ratio ranging from 3.5 to 7.2 produces similar temperature increases, signifying a global reaction rate independent of oxygen. The phenomenon of oxygen independence was then inspected by a three-step reduced mechanism and is attributed to a special role of H + O-2 M HO2 + M. This particular reaction dominating H and O-2 consumption with a fast rate is responsible for the concurrence of independences of its reaction coefficient, H, and O-2 to global reaction rate. Another property that HO2 quantity indicates reactive intensity was investigated by a two-step reduced mechanism and is credited to a small activation energy of reaction HO2 + HO2 H2O2 + O-2 and a thermal system.