Eutectic Freeze Desalination with Intermediate Cold Liquid
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Solution Overview
Problem
Current desalination technologies face challenges in efficiently handling highly concentrated brines due to high energy consumption, operational problems, and environmental impacts, particularly in the oil and gas industry, where existing methods struggle with fouling, corrosion, and low efficiency when dealing with high total dissolved solids (TDS) concentrations.
Innovation Solution
A zero-liquid discharge eutectic freeze desalination method using a single-stage or two-stage freezing process with intermediate-cold-liquid (ICL), where the brine is contacted with cooled ICL to form a slurry, separating ice and brine, and recycling the ICL, allowing for efficient separation and melting of ice to produce desalinated water while removing solid salts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal or membrane-based desalination technologies are used for highly concentrated brines, then desalination can be achieved, but operational problems such as fouling and corrosion occur along with lower efficiencies
Solution Approach 1:
The invention changes the fundamental parameter of the desalination approach from thermal/membrane processes to freezing-based separation. By lowering the temperature parameter and utilizing phase change, the system achieves effective separation of ice crystals from concentrated brine without the fouling and corrosion issues that plague thermal and membrane systems at high TDS concentrations
Solution Approach 2:
The invention exploits the phase transition of water from liquid to solid (freezing) to achieve desalination. Pure water freezes into ice crystals while salts remain in the liquid brine phase, enabling natural separation without membranes or thermal evaporation that cause operational problems in high-salinity conditions
2Use of energy by moving object
If direct contact freezing systems are used, then very large heat transfer coefficients are achieved, but the purified water contains excessive amounts of refrigerant that are hard to separate
Solution Approach 1:
The invention introduces an intermediate heat transfer fluid that acts as a mediator between the refrigeration system and the brine. This intermediary fluid absorbs heat from the brine through heat exchange surfaces, enabling efficient heat transfer while preventing direct contact between the refrigerant and the water being purified, thus maintaining high water quality
Solution Approach 2:
The invention replaces the direct mechanical mixing and contact of refrigerant with brine (as in direct contact freezing) with a thermal field-based heat exchange system. By substituting direct contact with indirect thermal coupling, the system achieves both efficient heat transfer and contamination-free purified water
3Productivity
If multi-stage distillation systems are used, then performance ratio is higher, but the significant increase in heat transfer area and large number of effects result in increased system complexity
Solution Approach 1:
The invention extracts and eliminates the complex multi-stage distillation system with its numerous heat transfer areas and effects. By adopting a single-stage freezing process, the system achieves desalination with significantly reduced complexity while maintaining effective separation performance through phase change rather than repeated evaporation-condensation cycles
4Quantity of substance
If existing desalination technologies are used for high TDS concentrations, then desalination can be performed, but fouling and corrosion problems occur along with lower efficiencies
Solution Approach 1:
The invention changes the operating parameter from ambient or elevated temperatures (thermal desalination) to sub-zero temperatures (freezing). This parameter change fundamentally alters the chemistry and physics of the process, preventing fouling and corrosion that occur in thermal and membrane systems while maintaining effective desalination capability for high TDS concentrations
Solution Approach 2:
By utilizing the phase transition of water to ice, the system naturally separates pure water from concentrated brine without requiring membranes or thermal processes that are susceptible to fouling and corrosion. The freezing process inherently rejects salts to the liquid phase, achieving desalination free from these harmful operational issues
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively addresses the limitations of existing technologies by providing a cost-competitive and energy-efficient solution for desalinating highly concentrated brines, producing high-quality purified water with reduced environmental impact and operational complexity.
Implementation Method 1
contacting the feed brine with the cooled ICL for a time sufficient to form a slurry of ice, brine, and ICL
Implementation Method 2
contacting the feed brine with the cooled ICL
Implementation Method 3
separating the ICL, ice and brine
Implementation Method 4
melting the separated ice to form desalinated water
Data Source
AI summary
A method for desalinating a brine includes the use of a cooled intermediate-cold-liquid (ICL), which combines with the brine in a crystallization or freezing tank to produce a slurry of ice, brine, and ICL. The method includes steps for separating the ICL, ice and brine, and returning the separated ICL to the source of cooled ICL tank. The method concludes with the steps of passing the separated brine to the crystallization tank, and melting the separated ice to form desalinated water. The method is significant in that it produces desalinated liquid water and solid salts. The combination of superior heat transfer with high quality purified water and competitive desalination economy makes the disclosed freeze desalination technology an attractive solution for desalination of highly concentrated brines produced in a variety of industries, including but not limited to the oil and gas industry and reject brine management.