Amine-Containing Composite Membranes for CO2/N2 Separation
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Solution Overview
Problem
Current membrane technologies face challenges in efficiently separating CO2 from N2 in flue gas, particularly in coal-derived flue gas, due to limitations in CO2/N2 selectivity and permeance, which hinders effective carbon capture and mitigation of carbon emissions.
Innovation Solution
Development of membranes comprising a gas permeable support layer and a selective polymer layer with a sterically hindered amine-containing polymer matrix, optionally incorporating graphene oxide, which enhances CO2 permeance and selectivity by facilitating CO2 transport through facilitated diffusion mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional membrane technologies are used for CO2 separation from N2, then the membrane structure is simple and easy to manufacture, but the CO2/N2 selectivity and permeance are insufficient
Solution Approach 1:
The patent employs a composite membrane structure consisting of a gas permeable support layer and a selective polymer layer. The support layer provides mechanical strength and gas permeability, while the selective polymer layer containing sterically hindered amine groups provides high CO2/N2 selectivity through facilitated diffusion mechanisms. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both high selectivity and structural feasibility.
Solution Approach 2:
The selective polymer layer is applied as a thin coating on the support layer, concentrating the separation function in a specific region. The sterically hindered amine groups are localized within the selective layer to provide targeted CO2 transport pathways. This local quality approach allows the membrane to achieve high CO2/N2 selectivity without requiring the entire membrane structure to be complex.
2Productivity
If conventional membranes are used, then the manufacturing process is simple, but the CO2 permeance is too low for efficient carbon capture
Solution Approach 1:
The patent modifies the chemical composition parameters of the membrane by incorporating sterically hindered amine groups into the selective polymer layer. This chemical parameter change enables facilitated diffusion of CO2, dramatically increasing CO2 permeance. The support layer's high intrinsic permeance (at least 25,000 GPU) also represents a parameter optimization that enhances overall CO2 transport efficiency while maintaining manufacturing feasibility through established coating techniques.
3Reliability
If a selective polymer layer is added to improve CO2 selectivity, then the separation performance increases, but the membrane structure becomes more complex
Solution Approach 1:
The membrane is segmented into two distinct functional layers: a gas permeable support layer and a selective polymer layer. Each layer is optimized for its specific function - the support layer provides mechanical integrity and baseline permeability, while the selective layer provides high CO2/N2 selectivity. This segmentation allows each component to be relatively simple while the combination achieves high performance.
Solution Approach 2:
The selective polymer layer is implemented as a thin film coating on the support layer. This thin film approach provides the necessary separation functionality with minimal added complexity and thickness. The flexible coating technique allows the selective layer to conform to the support layer structure, maintaining simplicity while achieving high CO2/N2 selectivity through the sterically hindered amine-containing polymer.
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 membranes achieve high CO2/N2 selectivity of at least 80 at 57-97°C and 1-6 bar feed pressure, enabling efficient CO2 capture from flue gas, thereby supporting effective carbon capture and reduction of carbon emissions.
Implementation Method 1
which enhances CO2 permeance and selectivity by facilitating CO2 transport through facilitated diffusion mechanisms
Implementation Method 2
graphene oxide can be nanoporous. The selective polymer layer can comprise from 0.01% to 5% by weight graphene oxide
Data Source
AI summary
Provided herein are gas permeable membranes comprising an amine-containing selective layer on top of a gas permeable polymer support as well as methods of making and using thereof. The membranes are useful for the separation of CO2 from N2-containing gases.