Abstract
This paper reports on the background and on the current status of an ongoing investigation that aims to provide reliable data for the operation of an SCWO reactor on an industrial scale. Based on successful experiences with the operation of a bench-scale SCWO reactor in the past, a new reactor containing a hydrothermal burner and transpiring walls was designed and built at ETH Zürich, Switzerland. This design was chosen in order to prevent plugging and to reduce corrosion of load-bearing walls or other functionally crucial parts of the reactor, respectively. Theoretical and experimental results from previous work also led to the conclusion that the flow rate of the flux through the transpiring walls strongly affects virtually every design parameter of an industrial reactor as well as the economic attractiveness of the process itself. As a first step, qualitative calculations were carried out under numerous simplifying assumptions. They showed that the additional operating costs caused by auxiliary fluids and by the energy for their pre-heating would be relevant in SCWO reactors with an aspect ratio L/D ≥ 5. Secondly, the overall setup and the key design features and dimensions of the new reactor were determined. Currently, an experimental procedure is being developed, in order to determine the influence of different process parameters on the global effectiveness of the SCWO process in reactors of said type.
