20170719_RO-PRO desalination : An integrated low-energy approach to seawater desalination...

1. Title, Journal and Authors

Title: RO-PRO desalination : An integrated low-energy approach to seawater desalination

Journal: Applied energy

Authors: Jeri L Prantea, Jeffrey A. Ruskowitza, Amy E. Childressb, Andrea Achillic,*

 a. Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557, USA
 b. Astani Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA 90089, USA

 c. Environmental Resources Engineering Department, Humboldt State University, Arcata, CA 95521, USA


2. Summary

 Even though reverse osmosis (RO) is currently the most energy efficient desalination technology, it is still an energy intensive process that requires a great deal of energy. In this context, pressure-retarded osmosis (PRO) is gaining an attention as a good measure to reduce the energy consumption of RO, so that many researchers are trying to put RO and PRO together to alleviate the energy problem and environmental issues related to RO. In this paper, the amount of energy production in PRO is evaluated in conjunction with RO and the results are shown in the unit of specific energy. To evaluate the performance of RO-PRO system accurately, well-characterized CTA membrane and a newly developed module-based PRO model were used. Consequently, it was found that the specific energy consumption of the hybrid system is approximately 40% lower than that of stat-of-the-art SWRO. In addition to it, a sensitivity analysis was performed to determine the effects of membrane characteristics on the specific energy production of the PRO process in the RO-PRO system and the results of the analysis showed that a minimum specific energy consumption of RO-PRO is around 1.0 kWh/m3 at 50% of recovery rate.


3. Originality & Creativity

 - The specific energy consumption of a RO-PRO system was modeled for the first time.

 - The minimum net specific energy consumption of the modeled RO-PRO system was 1.2 kWh/m3 at 50% RO recovery.

 - A sensitivity analysis showed a min RO-PRO specific energy consumption of 1.0 kWh/m3 and a max power density of 10 W/m2.


4. Application to research

 - According to the recent studies, we are already close to the energy limit of RO process at which can be achieved with an enhanced membrane property. Therefore, it is imperative for us to pave a new way that overcome the problem. The results shown in the current study can be a new sign that can lead us to overcoming the energy issue of desalination


5. Contact

 Sung Ho Chae (Ph.D. program)
Environmental Systems Engineering Lab.
School of Environmental Science & Engineering
Gwangju Institute of Science and Technology
1 Oryong-dong Buk-gu Gwangju, 500-712, Korea
Phone : +82-10-8734-8657
E-mail : kha5s@gist.ac.kr
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