Optimal design of a supercritical water gasification reactor for enhanced desalination

Salt deposition in supercritical water gasification reactors poses significant challenges, including heat transfer degradation and corrosion. This study introduces a novel reactor design characterized by an enhanced porous transpiring inner wall and a staged preheated water inlet from top to bottom. Computational fluid dynamics and discrete phase modeling are utilized to optimize the reactor design by investigating the flow field under various structural parameters. The results demonstrate that the proposed design effectively prevents salt accumulation on the inner reactor surface, confirming its effectiveness in reducing inorganic salt deposition. The height-to-diameter ratio emerges as the most critical parameter affecting the flow field, with significant impacts observed within nozzle lengths of 50 to 200 mm, nozzle diameters of 4 to 10 mm, and height-to-diameter ratios of 4.2 to 17.3. Furthermore, the analysis of desalination rates reveals that enhancing overall desalination performance depends on improving efficiency at the nozzle positions, given specific initial salt concentrations in the feed. This research is expected to provide valuable insights for optimizing reactor design to address salt deposition challenges effectively. [Display omitted] •A CFD-DPM model is developed to analyze the flow field in the reactor.•Salt particles are not deposited on the porous evaporative walls of the reactor.•Effects of different nozzle structures and height to diameter ratios are analyzed.•The system desalination efficiency is mainly determined at the nozzle location.