A desalination system with efficiency approaching the theoretical limits

Davies, Philip A., Wayman, James, Alatta, Chioma, Nguyen, Kim and Orfi, Jamel (2016). A desalination system with efficiency approaching the theoretical limits. Desalination and Water Treatment, Latest ,

Abstract

The objective of this project is to design a new desalination system with energy efficiency approaching the theoretical thermodynamic limit—even at high recovery ratio. The system uses reverse osmosis (RO) and a batch principle of operation to overcome the problem of concentration factor which prevents continuous-flow RO systems from ever reaching this limit and thus achieving the minimum possible specific energy consumption, SEC. Batch operation comprises a cycle in three phases: pressurisation, purge, and refill. Energy recovery is inherent to the design. Unlike in closed-circuit desalination (CCD), no feedwater is added to the pressure circuit during the pressurisation phase. The batch configuration is compared to standard configurations such as continuous single-stage RO (with energy recovery) and CCD. Theoretical analysis has shown that the new system is able to use 33% less energy than CCD at a recovery ratio of 80%. A prototype has been constructed using readily available parts and tested with feedwater salinities and recovery ratios ranging from 2,000 to 5,000 ppm and 17.2–70.6%, respectively. Results compare very well against the standard configurations. For example, with feedwater containing 5,000 ppm NaCl and recovery ratio of 69%, a hydraulic SEC of 0.31 kWh/m3 was obtained—better than the minimum theoretically possible with a single-stage continuous flow system with energy recovery device.

Publication DOI: https://doi.org/10.1080/19443994.2016.1180482
Divisions: Engineering & Applied Sciences > Mechanical engineering & design
Engineering & Applied Sciences > Engineering systems & management
Engineering & Applied Sciences > Sustainable environment research group
Engineering & Applied Sciences > Polymer and advanced materials research group
Additional Information: This is an Accepted Manuscript of an article published by Taylor & Francis in Desalination and Water Treatment on 9/5/16, available online: http://www.tandfonline.com/10.1080/19443994.2016.1180482
Uncontrolled Keywords: batch desalination,brackish water,high efficiency,high recovery,RO,solar,sustainable development,Pollution,Water Science and Technology,Ocean Engineering
Full Text Link: http://www.tand ... 94.2016.1180482
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
Published Date: 2016
Authors: Davies, Philip A. ( 0000-0003-4783-1234)
Wayman, James
Alatta, Chioma
Nguyen, Kim
Orfi, Jamel

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