(728a) Techno-Economic Analysis of Clathrate Hydrate Based Desalination (HyDesal) Process Utilizing LNG Cold Energy

Ponnivalavan Babu¹, Zheng Rong Chong¹, Abhishek Nambiar¹, Nagu Daraboina², Praveen Linga¹*

¹Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore 117 585

²Russell School of Chemical Engineering, The University of Tulsa, 800 South Tucker Drive, Tulsa, OK 74104, USA

Keywords: gas hydrates; desalination; clathrate process; seawater, cold energy, LNG, hydesal

*corresponding author: e-mail: praveen.linga@nus.edu.sg (P. Linga); Tel: (65) 6601-1487; Fax: (65) 6779-1936.

Abstract

Desalination is one of the most promising technologies to mitigate an emerging water crisis. Thermal desalination and reverse osmosis are two of the most widely employed desalination technologies in the world. However, these technologies are energy intensive. In countries like Singapore which lack natural water and energy resources, it is imperative to develop innovative energy-efficient technologies to strengthen the energy-water nexus. Clathrate hydrate based desalination (HyDesal) is one such technology.

Clathrate hydrate based desalination (HyDesal) process is based on a liquid to solid phase change by employing a suitable guest gas/ gas mixture for the phase change. In the HyDesal process, water molecules form cages around a guest gas/liquid component effectively rejecting salts present in the brine solution at temperatures slightly higher than normal freezing temperature of water. These crystals when dissociated or melted are essentially fresh water and the guest component can be re-used for the process again. While HyDesal process was proposed almost 50 years ago, it was never commercialized primarily due to the high energy requirement for low temperature operation, slow hydrate formation kinetics and inefficient hydrate crystal separation from brine. Recently, we proposed an innovative clathrate hydrate based desalination utilizing LNG cold energy with enhance water recovery based on the ability of propane to draw dispersed water from the sand bed towards the gas phase for hydrate growth.

In this presentation, we will present the techno-economic analysis of the clathrate hydrate based desalination utilizing the waste LNG cold energy. We will present the optimized conditions and the state-of-the-art prototype validation for HyDesal process along with detailed energy and cost analysis.