Date of Award

2020

Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Mechanical Engineering (MS)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Sajjad Bigham

Committee Member 1

Fernando Ponta

Committee Member 2

Kazuya Tajiri

Abstract

State-of-the-art zero liquid discharge (ZLD) technologies are currently bound with either intensive use of high-grade electrical energy such as mechanical vacuum vapor compressors utilized in brine crystallizers or high capital cost with environmental concerns such as evaporation ponds. The present study aims to address these issues by an innovative desiccant-based ZLD system in which a multiple-effect distillation (MED) unit is uniquely embedded at the heart of an absorption-desorption system. Here, the MED and absorption systems are inherently coupled enabling both heat and mass transfer processes between a high-salinity water and a desiccant solution. The proposed technology employs an absorption-based thermally-driven vapor compressor concept to pressurize the vaporized brine of the ZLD unit from a low-pressure absorber to a high-pressure desorber. The vacuum environment required for the ZLD treatment is established by strong hygroscopic properties of an aqueous lithium bromide (LiBr) salt. This eliminates the need for energy-intensive electrically-driven mechanical vapor compressors currently employed in advanced brine crystallizers. Comprehensive thermodynamic modeling has been performed to evaluate energy efficiency and size of the system. Insights gained from the present study have a high potential to truly transform thermal desalination and, in particular, ZLD treatment industries.

Available for download on Thursday, April 22, 2021

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