OXIDATION REACTIONS OF SOLID CARBON IN SUPERCRITICAL WATER

Abstract

ABSTRACT Compared to the research for homogeneous phase supercritical water oxidation (SCWO), kinetic understanding of SCWO progress on solid materials is less developed. We studied the reaction progress of carbon particles under SCWO conditions, where mass transfer processes and heterogeneous reactions are involved with mutual interactions. Reaction progress under mass-transfer limited conditions was observed for solid activated carbon at 400–500°C. The overall reaction of synthetic graphite observed at 500–600°C and that of activated carbon below 400°C were controlled by the internal surface heterogeneous reaction. The reaction rate at a unit internal surface area was proportional to the oxygen concentration and the specific reaction rate was described as 1.7 × exp (− 117 kJ mol−1/RT) m s−1. The reaction product was exclusively CO2 with a small amount of CO in the case of activated carbon.