Epoxy Amine Membrane for Aromatics Separation
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Solution Overview
Problem
Conventional polymeric membrane compositions used for separating hydrocarbon streams are unstable in the presence of alcohols and face challenges in achieving high flux and selectivity, particularly for aromatics separation, which hinders their commercial viability.
Innovation Solution
A polymeric membrane composition comprising polyethylene oxide (PEO), polypropylene oxide (PPO), or their co-polymers reacted with epoxides, such as tris(4-hydroxyphenyl)methane triglycidyl ether, is developed, providing improved stability and performance in alcohol-containing environments, with selectivity greater than 3.0 and suitable for separating aromatics from hydrocarbon streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymeric membrane compositions are used for separating hydrocarbon streams, then separation can be performed, but the membrane becomes unstable in the presence of alcohols
Solution Approach 1:
The patent employs composite membrane materials comprising polyethylene oxide (PEO) and polypropylene oxide (PPO) in specific ratios (30-70 wt% PEO and 70-30 wt% PPO), crosslinked with epoxides to create a composite structure that combines the advantages of both polymers. This composite approach enables the membrane to maintain structural stability while being compatible with alcohol-containing feeds, directly resolving the contradiction between reliability and adaptability.
Solution Approach 2:
The patent optimizes specific parameters including the PEO:PPO weight ratio (30-70/70-30), crosslinking density (using 0.5-5 wt% epoxy relative to polymer), and membrane thickness (10-100 micrometers). These parameter adjustments enable the membrane to achieve both stability and alcohol compatibility, transforming the conventional membrane properties to resolve the technical contradiction.
2Productivity
If membrane composition is optimized for high flux and selectivity, then separation performance improves, but physical integrity and stability deteriorate
Solution Approach 1:
The patent applies preliminary crosslinking treatment to the PEO-PPO membrane matrix before deployment. The epoxide crosslinking agents form a preliminary stable network structure that prevents membrane degradation during operation. This preliminary action ensures both high flux/selectivity performance and maintained physical integrity throughout the membrane's service life.
Solution Approach 2:
The patent creates local quality variations through controlled crosslinking density within the membrane structure. The crosslinked regions provide structural integrity and stability, while the non-crosslinked or less-crosslinked regions maintain high permeability and selectivity. This spatial differentiation of properties resolves the contradiction between productivity and stability.
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
The membrane composition demonstrates superior separation performance and durability in ethanol-containing gasoline fuels, maintaining high selectivity and flux, even in the presence of high alcohol content, offering a cost-effective alternative to traditional separation methods.
Implementation Method 1
The membrane is typically exposed at one side to a stream comprised of a mixture of liquid feeds, and a vacuum is typically applied to the membrane at the opposite side so that the adsorbed component migrates through the membrane and is removed as a vapor from the opposite side of the membrane via a solution-diffusion mechanism.
Implementation Method 2
a desired feed component, e.g., an aromatic component, of a liquid and/or vapor feed is preferentially absorbed by the membrane
Implementation Method 3
In the pervaporation process, a desired feed component, e.g., an aromatic component, of a liquid and/or vapor feed is preferentially absorbed by the membrane. The membrane is typically exposed at one side to a stream comprised of a mixture of liquid feeds, and a vacuum is typically applied to the membrane at the opposite side so that the adsorbed component migrates through the membrane and is removed as a vapor from the opposite side of the membrane
Implementation Method 4
In this process, the driving mechanism for the separation of the stream into separate products is provided by a concentration gradient exerted across the membrane. Certain components of the fluid will preferentially migrate across the membrane because of the physical and compositional properties of both the membrane and the process fluid, and will be collected on the other side of the membrane as a permeate.
Data Source
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AI summary
The present invention is directed to a membrane for aromatics separation that is stable in an alcohol containing environment. The polymeric membrane is a epoxy amine based membrane.