Destruction of hazardous waste in supercritical water. Part 2, A study of high-pressure methanol oxidation kinetics

In supercritical water oxidation, dilute aqueous organic wastes are oxidized at temperatures and pressures above the critical point of water. This process has been successfully demonstrated to treat waste streams of interest to the Department of Energy production facilities. In this paper we present a numerical study on the oxidation kinetics of a waste containing 98% water and 2% methanol under supercritical conditions. The plug-flow reactor model is similar to that presented in an earlier publication. We have corrected the chemistry in this model by changing the reaction rates of unimolecular reactions to their high-pressure limits. Our results show that the decomposition step of H{sub 2}O{sub 2} into the OH radical is the dominant reaction step controlling the destruction of methanol under supercritical conditions. Using the corrected chemistry model, we calculate the characteristic destruction times of methanol as a function of reactor inlet conditions.