Gas Separation Membrane with Hydrophilic Layer for BTX Resistance
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Solution Overview
Problem
Existing gas separation membranes face challenges in maintaining high gas permeability and selectivity, particularly when separating carbon dioxide from mixed gases containing BTX (benzene, toluene, xylene) components, which affect membrane life due to dissolution and diffusion mechanisms.
Innovation Solution
A gas separation membrane with a hydrophilic layer formed from polymers like polyvinyl alcohol, polyacrylic acid, or polysaccharides on a support, combined with a main body layer of polyimide or cellulose resin, and a mixed layer for enhanced adhesion and stability, ensuring high gas separation selectivity and prolonged membrane life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a gas separation membrane uses a dissolution and diffusion mechanism for separating carbon dioxide from methane, then gas separation selectivity is improved, but membrane life is reduced due to BTX (benzene, toluene, xylene) components in the mixed gas
Solution Approach 1:
The separating layer is divided into two distinct layers: a main body layer containing the dissolution-diffusion mechanism material for high selectivity, and a hydrophilic layer containing hydrophilic polymer for BTX resistance. This segmentation allows each layer to perform its specialized function independently, resolving the contradiction between selectivity and membrane life
Solution Approach 2:
The patent creates a composite membrane structure combining materials with different properties: the main body layer uses materials optimized for CO2/CH4 separation (dissolution-diffusion mechanism), while the hydrophilic layer uses hydrophilic polymers that resist BTX penetration. This composite approach allows the membrane to simultaneously achieve high selectivity and extended life in BTX-containing gases
2Productivity
If the separating layer is made thinner to improve gas permeability, then productivity is improved, but gas separation selectivity may be reduced
Solution Approach 1:
The patent addresses the thickness-selectivity tradeoff by introducing a new dimensional approach: instead of relying solely on the thickness of a single layer, it creates a multi-layer structure where the hydrophilic layer (thickness: 0.1-10 μm) protects the main body layer (thickness: 0.5-20 μm). This allows the main body layer to be optimized for selectivity while the hydrophilic layer provides additional functional protection, enabling high permeability without sacrificing selectivity
3Reliability
If a hydrophobic surface modification is applied to protect the membrane from moisture, then reliability is improved, but gas separation performance is reduced due to BTX interaction
Solution Approach 1:
Instead of using hydrophobic modification as conventionally done for moisture protection, the patent inverts the approach by applying a hydrophilic layer. This hydrophilic layer has the unique property of being resistant to BTX (benzene, toluene, xylene) components while still providing moisture protection, thereby improving both reliability and gas separation performance in BTX-containing mixed gases
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 achieves excellent gas permeability and selectivity with extended life, effectively handling mixed gases containing BTX, reducing operational costs and maintenance needs.
Implementation Method 1
the hydrophilic layer being disposed on the far side of the support and containing a hydrophilic polymer
Implementation Method 2
the influence of BTX is significant to a raw material of the membrane that relies on a dissolution and diffusion mechanism for gas separation
Data Source
AI summary
A gas separation membrane containing a support and a separating layer formed on the support,the separating layer containing a main body and a hydrophilic layer;the main body being disposed on the side of the support;the hydrophilic layer being disposed on the far side of the support and containing a hydrophilic polymer.