Gas Separation Membrane Sheet Aspect Ratio and Spacer Volume
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Solution Overview
Problem
Existing gas separation technologies face challenges in effectively separating CO2 and higher alkanes from methane with high selectivity and flux rate, particularly in humid environments, due to issues with membrane stability and gas permeability.
Innovation Solution
The development of gas separation elements comprising a membrane sheet with a porous support and a discriminating polysiloxane layer, where the membrane sheet has an aspect ratio of at least 1.5 and the permeate spacer has an open space volume of at least 0.0004 m3/m2, enhancing the separation efficiency and robustness in humid conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional membrane sheets are used for gas separation, then gas separation can be achieved, but the membrane stability and selectivity in humid environments deteriorates
Solution Approach 1:
The membrane sheet is constructed as a composite material comprising a porous support layer and a discriminating polysiloxane layer. The porous support provides mechanical strength and structural stability, while the polysiloxane layer provides gas separation selectivity and resistance to humid environment degradation. This composite structure resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The porous support layer with controlled pore structure provides both mechanical integrity and pathways for gas transport. The porosity is optimized to maintain membrane stability while allowing efficient gas permeation, resolving the contradiction between structural stability and gas separation performance in humid conditions.
2Reliability
If membrane sheets with higher selectivity are used, then CO2 and higher alkane separation improves, but flux rate deteriorates
Solution Approach 1:
The aspect ratio of the membrane sheet is optimized to at least 1.5, which changes the geometric parameters of the membrane structure. This parameter optimization allows the membrane to achieve both high selectivity for CO2 and higher alkanes over methane and adequate flux rate by improving gas distribution and reducing transport resistance.
Solution Approach 2:
The discriminating polysiloxane layer is applied selectively on the porous support to create local regions of high selectivity. The layer thickness and composition are locally optimized to maximize CO2 and higher alkane permeation while maintaining appropriate flux rates, resolving the contradiction between selectivity and productivity.
3Quantity of substance
If permeate spacer with smaller open space volume is used, then module density improves, but separation efficiency deteriorates
Solution Approach 1:
The open space volume of the permeate spacer is optimized to at least 0.0004 m3/m2, which is a specific parameter threshold that balances module density and separation efficiency. This parameter optimization ensures adequate space for permeate collection and transport while maintaining compact module design.
Solution Approach 2:
The permeate spacer structure is designed with optimized three-dimensional geometry to maximize open space volume within the available module space. By optimizing the spatial arrangement and dimensional proportions of the spacer, the design achieves both high module density and adequate separation efficiency simultaneously.
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 solution provides robust, stable gas separation elements with improved permeance and selectivity for CO2 and higher alkanes over methane, maintaining performance in humid environments and ensuring efficient gas separation and purification.
Implementation Method 1
a membrane sheet for separating a feed gas mixture into a permeate which has passed through a membrane and into the permeate spacer and a retentate which does not pass through the membrane
Data Source
AI summary
A gas separation element comprising a membrane sheet and a permeate spacer, wherein the membrane sheet comprises a porous support and a discriminating layer, CHARACTERISED IN THAT:(a) the permeate spacer has an open space volume of at least 0.0004 m3/m2; and(b) the membrane sheet has an aspect ratio of at least 1.5.