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Theoretical Analysis of a Mathematical Relation between Driving Pressures in Membrane-Based Desalting Processes
Sung Ho Chae1,2, Joon Ha Kim1
1School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.
Membranes
|April 3, 2021
Summary
This study establishes a mathematical relationship between driving pressures in membrane-based desalting processes like forward osmosis (FO) and reverse osmosis (RO). It identifies new constraints and optimization strategies for improved efficiency.
Area of Science:
- Membrane Science and Technology
- Water Treatment Technologies
- Chemical Engineering
Background:
- Osmotic and hydraulic pressures are critical for membrane-based desalting (forward osmosis, FO; pressure-retarded osmosis, PRO; reverse osmosis, RO).
- A clear understanding of the relationship between these driving pressures and their impact on system performance has been lacking.
- Existing analyses of driving pressure effects on desalting systems are insufficient due to the absence of a defined pressure-performance relationship.
Purpose of the Study:
- To formulate a precise mathematical relationship between driving pressures in membrane-based desalting processes.
- To account for energy losses within each driving pressure component.
- To provide a theoretical framework for analyzing and optimizing these critical water treatment technologies.
Main Methods:
- Definition of pseudo-driving pressures to represent water transport direction.
- Introduction of similarity coefficients to quantify energy conservation principles.
- Development of a mathematical model linking osmotic and hydraulic pressures with energy considerations.
Main Results:
- A novel mathematical relation between driving pressures in FO, PRO, and RO processes has been established.
- Three new theoretical constraints essential for operating membrane-based desalting systems were identified.
- The study quantifies energy conservation through similarity coefficients, aiding in system analysis.
Conclusions:
- The established mathematical relation and identified constraints offer crucial guidelines for optimizing membrane-based desalting processes.
- Analysis of similarity coefficients highlights the commercial advantages of reverse osmosis (RO) over forward osmosis (FO) and pressure-retarded osmosis (PRO).
- This research provides a foundation for developing detailed optimization strategies by linking membrane and operational parameters for enhanced water treatment efficiency.
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