Resource recovery from desalination brine: energy efficiency and purification process integration for sodium hydroxide production
Name
Preprint-DU-EST-April-2018-rev.pdf
Size
598.35 KB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Du, Fengmin
Warsinger, David Elan Martin
Urmi, Tamanna I.
Thiel, Gregory Parker
Kumar, Amit
Lienhard, John H
Alternative Title
Sodium Hydroxide Production from Seawater Desalination Brine: Process Design and Energy Efficiency
Date Issued
April 2018
Journal
Environmental Science & Technology
Publisher
American Chemical Society (ACS)
Citation
F. Du et al. “Sodium hydroxide production from seawater desalination brine: process design and energy efficiency,” Environmental Science & Technology, 52, 10 (April 2018): 5949–5958 © 2018 American Chemical Society
Version
Author's final manuscript
Abstract
The ability to increase pH is a crucial need for desalination pretreatment (especially in reverse osmosis) and for other industries, but processes used to raise pH often incur significant emissions and nonrenewable resource use. Alternatively, waste brine from desalination can be used to create sodium hydroxide, via appropriate concentration and purification pretreatment steps, for input into the chlor-alkali process. In this work, an efficient process train (with variations) is developed and modeled for sodium hydroxide production from seawater desalination brine using membrane chlor-alkali electrolysis. The integrated system includes nanofiltration, concentration via evaporation or mechanical vapor compression, chemical softening, further ion-exchange softening, dechlorination, and membrane electrolysis. System productivity, component performance, and energy consumption of the NaOH production process are highlighted, and their dependencies on electrolyzer outlet conditions and brine recirculation are investigated. The analysis of the process also includes assessment of the energy efficiency of major components, estimation of system operating expense and comparison with similar processes. The brine-to-caustic process is shown to be technically feasible while offering several advantages, that is, the reduced environmental impact of desalination through lessened brine discharge, and the increase in the overall water recovery ratio of the reverse osmosis facility. Additionally, best-use conditions are given for producing caustic not only for use within the plant, but also in excess amounts for potential revenue.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Rohsenow Kendall Heat Transfer Laboratory (Massachusetts Institute of Technology)
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1021/acs.est.8b01195
