Supercritical Water Oxidation (SCWO) for the Removal of Nitrogen Containing Heterocyclic Waste Hydrocarbon Part II: System Kinetics

This work investigated supercritical water oxidation (SCWO) of DBU (C9H16N2)1 in the absence and presence of isopropyl alcohol (IPA) as co-fuel. SCWO was studied in a plug-flow reactor under different temperatures (400–525 °C), initial DBU concentrations (1–10 mM at reactor conditions), oxidant ratios (0.8–2), and [IPA]0/ [DBU]0 ratios (0.5–4). Pseudo First Order and the Global Power Law models expressed the kinetics, and the rate constants were evaluated. Furthermore, SCWO of aqueous ammonia (NH4+) as feedstock was studied at several temperatures (400–500 °C), oxidant ratios (0.8–2.0) and [IPA]0/[NH4+]0 ratios; and the same kinetic models were applied. Results showed that IPA addition increased the reaction rate constant k, affected oxidant utili- sation, and greatly enhanced NH4+ removal% towards gaseous nitrogen. The influence of IPA addition was more pronounced on N-speciation than it was on TOC% removal, for all current system conditions.