Supercritical water desalination (SCWD): process development, design and pilot plant validation

Conventional desalination technologies such as reverse osmosis (RO), multi-stage flash distillation (MSF) and electro dialysis (ED) have a major drawback; the production of a liquid waste stream with an increased salinity (compared to the feed) that has to be disposed of. The treatment of this waste stream has always presented technical, economic and environmental challenges. With stricter environmental regulations regarding brine disposal into water bodies, the treatment or disposal of this waste stream pose a huge challenge for the sustainability of desalination methods. Currently, research studies are being conducted to develop zero liquid discharge (ZLD) technologies for desalination. Supercritical water desalination (SCWD) is a new desalination method that allows for the treatment of salt water streams with ZLD. The work presented in this thesis focuses on the process development (conceptual design of the process, lab-scale demonstration of the proof-of-concept, and selection of process operating pressure and temperature), design and construction of a pilot SCWD unit, and the first results from this pilot plant. Essential insights into the heat transport mechanism (essential for heat integration) of SCW flow at low mass fluxes encountered in such pilot unit are provided. With the pilot plant demonstration of the SCWD process introduced in this thesis, a new approach to tackle desalination in a sustainable way with Zero Liquid Discharge is provided.