Laminated Gas Separation Membrane for Film Formability and Permeability
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Solution Overview
Problem
Existing gas separation methods using hydrophobic porous membranes face issues with uniform coating and gas permeability due to poor wettability, while hydrophilic porous membranes suffer from gel layer penetration into pores under pressure, leading to reduced permeability.
Innovation Solution
A laminated gas separation apparatus with a hydrophilic porous membrane supporting a separation-functional layer and a hydrophobic protective membrane is used, where the hydrophilic membrane is on the high-pressure side to prevent gel layer penetration into pores, maintaining film formability and gas permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hydrophilic porous membrane is used as the supporting membrane, then the cast solution can be uniformly coated on the supporting membrane, but the cast solution flows into the pores of the supporting membrane, causing the gel layer to penetrate into the pores and reduce gas permeability
Solution Approach 1:
The membrane structure is divided into three distinct layers: a hydrophilic porous membrane for uniform coating, a gel layer for separation functionality, and a hydrophobic porous membrane to prevent penetration. This segmentation allows each layer to perform its specific function without interfering with others, resolving the contradiction between film formability and gas permeability.
Solution Approach 2:
The hydrophobic porous membrane acts as an intermediary barrier between the gel layer and the external environment. It prevents the gel layer from penetrating into the pores while allowing the cast solution to uniformly coat the hydrophilic supporting membrane during the formation process.
2Productivity
If a hydrophobic porous membrane is used as the supporting membrane, then gas permeability is maintained, but the wettability is poor, making it difficult to uniformly coat the cast solution
Solution Approach 1:
The membrane is segmented into functional layers where the hydrophilic porous membrane handles the coating process and the hydrophobic porous membrane handles gas permeability. This division of labor allows each layer to optimize its specific function without compromise.
Solution Approach 2:
Different regions of the membrane structure have different properties: the hydrophilic side facing the cast solution for uniform coating, and the hydrophobic side facing the gas stream for maintaining permeability. This local differentiation of properties resolves the contradiction between wettability and gas permeability.
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 effectively suppresses gas permeability deterioration while preserving the hydrophilic membrane's film formability by preventing gel layer penetration, enhancing CO2/N2 selectivity and permeance.
Implementation Method 1
when a hydrophilic porous membrane is used as the supporting membrane, the cast solution can be uniformly coated on the supporting membrane
Implementation Method 2
the wettability of the hydrophobic supporting membrane is poor, it is difficult to uniformly coat the cast solution on the supporting membrane
Implementation Method 3
separating the gas to be separated from the mixed gas by having the gas to be separated permeate from a first treatment chamber side of the selective permeable membrane to a second treatment chamber side
Implementation Method 4
a selective permeable membrane provided with a separation-functional layer that is selectively permeable to the gas to be separated
Implementation Method 5
a first protective membrane of a hydrophobic porous membrane laminated on the separation-functional layer are stacked in order
Data Source
AI summary
A gas separation method is provided. The method includes using a gas separation apparatus comprising a selective permeable membrane and a first and second treatment chambers separated by the selective permeable membrane. A mixed gas containing a gas to be separated is supplied into (or generated within) the first treatment chamber, and the gas to be separated is separated from the mixed gas by having the gas to be separated permeate from the first/second treatment chamber side of the selective permeable membrane, which has a stacked laminated structure of a hydrophilic porous membrane, a separation-functional layer, and a first protective membrane, and the separation-functional layer includes a layer of hydrophilic polymer containing water, and the first treatment chamber is provided on a hydrophilic porous membrane side of the selective permeable membrane and the second treatment chamber is provided on the first protective membrane side of the selective permeable membrane.