Hydrate-based desalination (HyDesal) process employing a novel prototype design

Water and energy are intricately interlinked and therefore it is imperative to develop sustainable technologies to strengthen water-energy nexus. One such industry where the energy - water nexus can be addressed is at Liquefied natural gas (LNG) regasification terminals. At the LNG regasification terminals, LNG is converted back to natural gas by heating using seawater which gets cooled during the process. This cooled seawater is dumped back to the sea leading to wastage of cold energy. One potential technology that can harvest and utilize this waste cold energy is the hydrate-based desalination (HyDesal) process. HyDesal process is based on a liquid to solid phase change by employing a suitable hydrate former for the phase change. While the HyDesal process was proposed almost 70 years ago, it was never commercialized primarily due to slow hydrate formation, inefficient hydrate crystal separation from brine and refrigeration. To address the above challenges, we proposed an innovative HyDesal process utilizing LNG cold energy with enhanced water recovery based on the unusual behavior of propane. In this study, we present the design and demonstration of a prototype for the HyDesal process. With our innovative prototype design, we carried out water recovery experiments and salt rejection studies. Water recovery of 34.85 (+/- 0.35)% and salt rejection of 87.5 (+/- 1.84)% was achieved with 3 wt% NaCl solution. (C) 2020 Elsevier Ltd. All rights reserved.