Fluorinated Membrane Dehydration of Organic Solutions
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Solution Overview
Problem
Current membrane technologies for dehydrating organic/water mixtures are inefficient due to hydrophilic membranes that swell or dissolve in aqueous environments, making them unusable even at low water concentrations, especially when the feed solution is hot, and are not economically viable for processes like bioethanol production and acetic acid recovery.
Innovation Solution
The use of hydrophobic fluorinated glassy polymer or copolymer membranes with a selective layer made from fluorinated cyclic structures, which maintain selectivity and permeance even at high water concentrations and temperatures, allowing for effective pervaporation or vapor-phase separation of water from organic compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrophilic membranes are used for dehydration, then water separation capability is improved, but membrane stability deteriorates due to swelling and dissolution in aqueous environments
Solution Approach 1:
The patent changes the fundamental parameter of membrane hydrophobicity by using fluorinated glassy polymers with contact angles greater than 90 degrees. This parameter change allows the membrane to maintain stability in aqueous environments while still achieving water separation through vapor-phase permeation, resolving the contradiction between water separation capability and membrane stability.
Solution Approach 2:
The patent utilizes phase transition by operating in the vapor-phase regime where water evaporates from the liquid feed and passes through the membrane as vapor. This phase transition approach allows hydrophobic membranes to effectively separate water without direct contact with liquid water, maintaining membrane stability while achieving dehydration.
2Productivity
If conventional membranes are used at high water concentrations, then dehydration capacity is improved, but membrane usability deteriorates due to swelling and loss of separation properties
Solution Approach 1:
The patent changes the membrane material parameter to fluorinated glassy polymers that are inherently resistant to swelling in water. This allows the membrane to maintain its separation properties and structural integrity even when processing feeds with high water concentrations, enabling both high dehydration capacity and sustained membrane usability.
3Speed
If hydrophilic membranes are used at elevated temperatures, then permeation rate is improved, but membrane performance deteriorates due to accelerated swelling and dissolution
Solution Approach 1:
The patent changes the thermal stability parameter of the membrane material by selecting fluorinated glassy polymers with high glass transition temperatures (above 100°C). This parameter change enables the membrane to withstand elevated operating temperatures without swelling or dissolution, maintaining both permeation rate and performance reliability simultaneously.
4Reliability
If distillation is used for dehydration, then separation effectiveness is improved, but energy consumption increases
Solution Approach 1:
The patent replaces the mechanical distillation system with a membrane-based separation system. This substitution eliminates the need for large-scale heating and phase change operations required by distillation, achieving comparable separation effectiveness with significantly reduced energy consumption through vapor-phase permeation through the hydrophobic membrane.
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
These membranes enable efficient dehydration of organic/water solutions by maintaining selectivity and permeance, effectively separating water from organic compounds across a wide range of concentrations and temperatures, reducing energy and cost requirements in industrial processes.
Implementation Method 1
The separation is performed under pervaporation conditions, in which the feed stream is in the liquid phase and the membrane permeate is in the vapor phase
Implementation Method 2
under vapor-phase conditions, in which the feed and permeate are in the vapor phase
Implementation Method 3
The membranes used in the process of the invention have selective layers made from a hydrophobic fluorinated glassy polymer or copolymer
Data Source
Figure 1~2
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AI summary
Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.