MSF Brine Reject Dilution in the Forward Osmosis Process: Performance Analysis

Khanafer, Daoud

MSF Brine Reject Dilution in the Forward Osmosis Process: Performance Analysis

Khanafer, Daoud

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Publication Type:: Thesis
Issue Date:: 2022

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Field	Value	Language
dc.contributor.author	Khanafer, Daoud
dc.date.accessioned	2023-04-14T01:47:03Z
dc.date.available	2023-04-14T01:47:03Z
dc.date.issued	2022
dc.identifier.uri	http://hdl.handle.net/10453/169791
dc.description	University of Technology Sydney. Faculty of Engineering and Information Technology.	en_US.UTF-8
dc.description.abstract	One of the largest global risks is freshwater scarcity. In countries with limited natural water resources, water reclamation and desalination have become a strategic source of clean and usable water. Specifically, seawater desalination is a sustainable flow of fresh water in the Gulf Cooperation Council (GCC) countries located in the driest part of the world. Multi-Stage Flashing (MSF) desalination has been proved to be the most reliable thermal desalination technology in the GCC countries, mainly considering Qatar’s MSF plants. Despite its efficiency and high-quality water production, MSF technology suffers major drawbacks affecting its performance. Scale formation, specifically the non-alkaline scale, has been a serious issue from thermodynamic and economic perspectives. Pretreatment of the feed solution to the MSF plants was proposed and investigated in the literature to tackle the scale issue. The current project's novelty is to design and test the FO-MSF hybrid system for seawater pretreatment by the FO process for the MSF desalination plant. Several commercial FO and NF membranes were applied for recycling the MSF brine reject within the FO system using the brine as a draw solution. Selecting the appropriate membrane and the ideal draw solution is essential for an efficient FO process. Since the brine reject solution is the only DS used in all the experiments conducted in this study, the variables included the membrane and the feed solution. TFC and CTA FO membranes with fresh sweater feed solution were used in the FO system for the MSF plant. Pressure-assisted FO (PAFO) process was introduced, and experimental results showed 50% more permeation flux by increasing the feed pressure from 1 to 4 bar. When tertiary sewage effluent (TSE) was proposed as a feed solution using TFC membranes, a considerably high water flux of 35 L/m²h was achieved. Under the same operating conditions in the FO mode using fresh seawater on the feed side, commercial NF membranes were tested for the first time in the FO system. A more feasible membrane selection can be the NF membranes as they demonstrated better results than FO membranes. However, higher performance was achieved when TSE and NF were combined in the FO process. Experimentally, this combination recorded a maximum water flux of 39.5 L/m2h and achieved up to 42% divalent ions dilution. While the outcome of this study is still preliminary, the results are promising and can highlight the potential of using the FO system for MSF brine dilution.	en_US.UTF-8
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/169791/2/02whole.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2022 Daoud Khanafer
dc.rights	au.edu.uts.lib/ppc
dc.title	MSF Brine Reject Dilution in the Forward Osmosis Process: Performance Analysis	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*
utslib.copyright.embargo	2023-12-31T00:00:00+1000

Abstract:

One of the largest global risks is freshwater scarcity. In countries with limited natural water resources, water reclamation and desalination have become a strategic source of clean and usable water. Specifically, seawater desalination is a sustainable flow of fresh water in the Gulf Cooperation Council (GCC) countries located in the driest part of the world. Multi-Stage Flashing (MSF) desalination has been proved to be the most reliable thermal desalination technology in the GCC countries, mainly considering Qatar’s MSF plants. Despite its efficiency and high-quality water production, MSF technology suffers major drawbacks affecting its performance. Scale formation, specifically the non-alkaline scale, has been a serious issue from thermodynamic and economic perspectives. Pretreatment of the feed solution to the MSF plants was proposed and investigated in the literature to tackle the scale issue. The current project's novelty is to design and test the FO-MSF hybrid system for seawater pretreatment by the FO process for the MSF desalination plant. Several commercial FO and NF membranes were applied for recycling the MSF brine reject within the FO system using the brine as a draw solution. Selecting the appropriate membrane and the ideal draw solution is essential for an efficient FO process. Since the brine reject solution is the only DS used in all the experiments conducted in this study, the variables included the membrane and the feed solution. TFC and CTA FO membranes with fresh sweater feed solution were used in the FO system for the MSF plant. Pressure-assisted FO (PAFO) process was introduced, and experimental results showed 50% more permeation flux by increasing the feed pressure from 1 to 4 bar. When tertiary sewage effluent (TSE) was proposed as a feed solution using TFC membranes, a considerably high water flux of 35 L/m²h was achieved. Under the same operating conditions in the FO mode using fresh seawater on the feed side, commercial NF membranes were tested for the first time in the FO system. A more feasible membrane selection can be the NF membranes as they demonstrated better results than FO membranes. However, higher performance was achieved when TSE and NF were combined in the FO process. Experimentally, this combination recorded a maximum water flux of 39.5 L/m2h and achieved up to 42% divalent ions dilution. While the outcome of this study is still preliminary, the results are promising and can highlight the potential of using the FO system for MSF brine dilution.

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