Evaluation of the recovery of osmotic energy in desalination plants by using pressure retarded osmosis

ABSTRACT

The current paper explores the possibility of using pressure retarded osmosis (PRO) as part of the post-treatment of existing desalination plants: a membrane-based PRO system would be used to transform osmotic energy of the retentate into hydraulic pressure; this pressure is then used to generate electricity in a turbine. For this, a source of water with lower osmotic pressure would be needed: municipal or industrial wastewater, brackish water, etc. From the point of view of implementation, except for the PRO membranes, this additional PRO post-treatment uses a small number of additional components, which are similar to those already standards in desalination industry. A model of the process is developed, and some feasibility studies will be discussed, to evaluate the potential for varying mixing rates.

Keywords:

• Energy recovery
• Desalination
• Pressure retarded osmosis

Acknowledgment

This work was partially funded by MiCInn project DPI2010-21589-c05.

Notes

Presented at the International Conference on Desalination for the Environment, Clean Water and Energy, European Desalination Society, 23–26 April 2012, Barcelona, Spain