A potential co-current mixing reactor design for supercritical water oxidation

Corrosion and salt agglomeration are primary obstacles prohibiting widespread industrial implementation of supercritical water oxidation (SCWO). These operational issues can be effectively overcome however, by controlling the mixing behaviour within the reactor. This article presents the use of both pseudo fluid and computational fluid dynamics (CFD) modelling approaches to simulate the general flow patterns and mixing regimes inside an innovative tube-in-tube co-current mixing reactor design. Both modelling techniques show evidence that corrosion on the internal surface of the reactor can be mitigated. A laboratory-scale reactor system was designed and fabricated to validate the modelling studies for application to SCWO. Results of scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray diffraction (XRD) indicated that the 1 m long co-current reactor was divided into two regions. The initial 25% of the reactor length was effectively protected by the flow of clean supercritical water. Near complete removal of the organic content of 2,4-dichlorophenol (2,4-DCP) was achieved under mild operating conditions. (C) 2019 Elsevier B.V. All rights reserved.