Design, Fabrication, and Operational Parameters of a Supercritical Water Oxidation Reactor

Thesis (Master's)--University of Washington, 2020Supercritical Water Oxidation (SCWO) has been shown to efficiently destroy wet organic wastes. The process, iterations, and lessons learned during the design and fabrication process of a continuous, inverted SCWO reactor are described. Ethanol is oxidized in a continuous inverted supercritical water oxidation reactor at 25 MPa, with oxidant and fuel preheat temperatures of 380 to 450 °C. Optimal conditions for future operation are found by operating at various premixed fuel concentrations of 0-7 mol% ethanol in water, varying the air to fuel equivalence ratio from 1.1 to 1.8, and utilizing air and hydrogen peroxide as the oxidant. Experimental conditions are chosen for analysis of reactor temperatures during complete oxidation of pilot fuel, where ethanol will rapidly oxidize. Higher premixed concentrations of ethanol produce a more localized, higher temperature reaction occurring closer to the nozzle with longer residence times. Preliminary results find the use of air results in lower reaction temperatures than hydrogen peroxide at similar operational conditions due to nitrogen loading; the experiments with air are still on-going. The results are used to determine the capability of the reactor for the destruction of toxic organic compounds