Practical aspects of batch RO design for energy-efficient seawater desalination
Author(s)Swaminathan, Jaichander; Tow, Emily W.; Stover, Richard L.; Lienhard, John H
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Batch operation of reverse osmosis (RO) has been proposed as a method to reduce seawater RO (SWRO) energy consumption and fouling propensity. In this paper, we use a transient numerical model of the RO process to investigate the impact of several practical loss mechanisms on the overall energetic performance of batch SWRO compared to a conventional continuous system. A critical variable that controls the energetic advantage of batch RO is the reset time between cycles. A large reset time necessitates higher operating flux and therefore results in increased energy consumption. On the other hand, ensuring a low cycle reset time requires higher energy for the refilling process. A batch SWRO design with an atmospheric pressure feed tank and pressure exchangers for energy recovery does not show promise for energy savings. Batch SWRO must be designed with a large number of short pressure vessels (with fewer membranes each) and lower energy recovery losses (e.g., by using pressurized feed storage) in order to reduce energy consumption by up to 8%. These modifications are more complex and hence capital expenses would determine the overall feasibility of such designs to improve seawater desalination. Keywords: Batch reverse osmosis; Energy consumption; Operation; Reset time
DepartmentMassachusetts Institute of Technology. Department of Mechanical Engineering; Rohsenow Kendall Heat Transfer Laboratory (Massachusetts Institute of Technology)
Swaminathan, Jaichander et al. "Practical aspects of batch RO design for energy-efficient seawater desalination." Desalination 470 (November 2019): 114097 © 2019 Elsevier B.V.
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