Gas Separation Membrane Layers for High Permeance and Leak Control
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Solution Overview
Problem
Existing gas separation membranes (GSMs) lack mechanical strength, flexibility, and efficiency in discriminating between gases, particularly at high temperatures, and are prone to defects and liquid leakage, necessitating improved design and materials for continuous operation.
Innovation Solution
A gas separation membrane comprising a porous substrate, a gutter layer of cross-linked polysiloxane polymer, a discriminating layer with at least 60 w/w % ethylene oxide groups and 0.15 mmol/g of thioether groups, and optionally a protective layer of cross-linked polysiloxane polymer, with specific thicknesses and properties to enhance mechanical strength, permeance, and gas discrimination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gel layer comprising a high amount of liquid is arranged on the polymer layer to improve gas discrimination, then selectivity between polar and non-polar gases is enhanced, but the liquid may leach out during use, polluting the retentate stream and reducing reliability
Solution Approach 1:
The patent introduces a protective layer comprising cross-linked polysiloxane polymer as an intermediary between the gel layer and the external environment. This protective layer acts as a barrier that prevents liquid leaching from the gel layer while allowing gas permeation, thus eliminating the harmful effect of liquid pollution without compromising gas discrimination capability
Solution Approach 2:
The patent employs a thin film protective layer made of cross-linked polysiloxane polymer that is permeable to gases but impermeable to liquids. This thin film structure allows the membrane to maintain flexibility and gas transport functionality while providing effective protection against liquid leaching
2Productivity
If the discriminating layer is made thinner to increase gas permeance, then flux properties improve, but mechanical strength and structural integrity are reduced
Solution Approach 1:
The patent applies local quality by creating a gutter layer with specific structural features (cross-section shape, thickness, and composition) at the interface between the porous support and discriminating layer. This localized structural optimization provides mechanical reinforcement exactly where needed to support the thin discriminating layer, enabling high permeance without sacrificing strength
Solution Approach 2:
The patent uses composite materials by combining the porous support layer, gutter layer with cross-linked polysiloxane polymer, and discriminating layer into a multi-layer composite structure. Each layer contributes specific properties: the porous support provides mechanical strength, the gutter layer provides localized reinforcement, and the thin discriminating layer provides high gas permeance and selectivity
3Strength
If the gutter layer thickness is increased to improve mechanical support, then structural integrity is enhanced, but gas permeance is reduced due to additional transport resistance
Solution Approach 1:
The patent employs a thin film gutter layer with optimized thickness (0.01-2.5 μm) that is sufficient to provide mechanical support and structural integrity while remaining thin enough to minimize gas transport resistance. The cross-linked polysiloxane polymer provides high mechanical strength per unit thickness, enabling the gutter layer to fulfill both support and permeability requirements
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 high permeance and selectivity for gas separation, particularly between polar and non-polar gases, with improved thermal stability and reduced defects, enabling efficient and continuous operation.
Implementation Method 1
a gutter layer comprising a cross-linked polysiloxane polymer
Implementation Method 2
a discriminating layer comprising at least 60 w/w % of ethylene oxide (EO) groups and at least 0.15 mmol/g of thioether groups... capable of discriminating well between gases (e.g. between polar and non-polar gases)
Implementation Method 3
The primary purpose of the porous substrate is to provide the GSM with mechanical strength without materially reducing gas permeance
Implementation Method 4
optionally a protective layer comprising a cross-linked polysiloxane polymer
Data Source
AI summary
A gas separation membrane comprising: (i) a porous substrate: (ii) a gutter layer comprising a cross-linked polysiloxane polymer; (iii) a discriminating layer comprising at least 60 w/w % of ethylene oxide (EO) groups and at least 0.15 mmol/g of thioether groups; and (iv) optionally a protective layer comprising a cross-linked polysiloxane polymer; wherein: (a) the gutter layer has an average thickness of less than 2.5 μm; and (b) the discriminating layer has an average thickness of greater than 0.2 μm and less than 5 μm.