A novel zero-liquid discharge desalination system based on the humidification-dehumidification process: a preliminary study

Abstract
As a byproduct of desalination plants, brine is increasingly becoming a threat to the environment, and the design of zero-liquid discharge desalination (ZLDD) systems is gaining increasing attention. Existing ZLDD systems are limited by a high energy intensity and high plant costs of their crystallizers. This study proposes a novel crystallization method based on the humidification-dehumidification (HDH) process, which exhibits the advantages of a low energy consumption, low component costs and a reduced scaling and fouling potential. A simple experimental setup is first designed to demonstrate the feasibility of the proposed system. Brine concentration and salt crystallization are successfully achieved with air heated to 40 ℃ as the heat source. Afterwards, a thermo-economic analysis is conducted for the whole system. The specific thermal energy and electricity consumption levels are found to range from 700-900 and 5-11 kJ, respectively, per kg of feed brine. The energy consumption is 56% lower than that of a conventional evaporative crystallizer, and the initial plant cost is reduced by 58%. Keywords: zero-liquid discharge desalination; crystallization; humidification-dehumidification.

Citation
Chen, Q., Akhtar, F. H., Burhan, M., Kumja, M., & Ng, K. C. (2021). A novel zero-liquid discharge desalination system based on the humidification-dehumidification process: a preliminary study. Water Research, 117794. doi:10.1016/j.watres.2021.117794

Acknowledgements
This research was supported by the Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST).

Publisher
Elsevier BV

Journal
Water Research

DOI
10.1016/j.watres.2021.117794

Additional Links
https://linkinghub.elsevier.com/retrieve/pii/S004313542100988X

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