Evaluation of the energy consumption of industrial hybrid seawater desalination process combining freezing system and reverse osmosis

Abstract

Desalination of seawater can provide an almost inexhaustible source of freshwater if it can be made affordable. This work is part of an innovative approach aimed at improving the seawater desalination cost through the development of a new method which is more efficient than the existing processes in use. A benchmarking study and a literature analysis were realized, and the results helped us in orientating research study toward the development of an industrial hybrid system coupling freezing and reverse osmosis (RO). The freezing process is proposed as a method of seawater pre-treatment for the RO membranes. It is coupled with a heat pump system which freezes the seawater inside a crystallizer and melts the ice in a melting chamber. By combining freezing and membrane desalination processes, the hybrid system has been successfully improved. The evaluation of the proposed systems’ energy consumption shows energy savings of approximately 25%, and an improvement of the quality of osmotic water for about 71% when compared to the conventional-RO desalination. This evaluation was conducted on the basis of mass and energy balances of the freezing process and simulation of the RO desalination process using a non-commercial software.

Keywords:

• Hybrid desalination
• Seawater
• Freezing
• Reverses osmosis
• Ice crystallization
• Energy consumption

Notes

Presented at the 4th Maghreb Conference on Desalination and Water Treatment (CMTDE 2013) 15–18 December 2013, Hammamet, Tunisia