Crosslinked PIM-Polyimide Membranes for CO2 Separation
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Solution Overview
Problem
Current polymeric membrane technologies for natural gas processing face limitations in achieving high permeability and selectivity for CO2 removal while maintaining resistance to plasticization, particularly under industrial conditions.
Innovation Solution
Development of blended polymeric membranes incorporating a crosslinked polymer of intrinsic microporosity (PIM) with a polyethylene glycol-bisazide crosslinking agent, specifically a 6FDA-based co-polyimide matrix, which enhances CO2 permeability and selectivity while reducing plasticization through thermal crosslinking via nitrene reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If polyimide membranes are used for gas separation, then selectivity for CO2 removal is improved, but permeability decreases and plasticization increases
Solution Approach 1:
The patent creates a composite membrane system by blending polyimide with crosslinked PIM polymers. This composite structure combines the high selectivity of polyimide with the high permeability of PIM, achieving CO2/CH4 selectivity above 30 and permeability exceeding 1000 GPU simultaneously. The crosslinked PIM domains provide microporous pathways for gas transport while the polyimide matrix maintains structural integrity and selectivity.
Solution Approach 2:
The patent utilizes crosslinked PIM polymers with intrinsic microporosity to create hierarchical pore structures within the membrane. These microporous regions provide preferential pathways for CO2 transport through size-sieving effects and enhanced gas-polymer interactions, significantly increasing permeability while maintaining selectivity through the controlled pore architecture.
2Measurement precision
If polyimide membranes are used for gas separation, then selectivity for CO2 removal is improved, but resistance to plasticization worsens
Solution Approach 1:
The patent develops a composite membrane where crosslinked PIM domains are dispersed within the polyimide matrix. The crosslinked PIM regions act as plasticization-resistant zones that maintain structural stability under high CO2 pressure, preventing the dense polyimide matrix from undergoing excessive plasticization while preserving the selective transport pathways.
Solution Approach 2:
The patent modifies the membrane's physical and chemical parameters by introducing crosslinked PIM with specific microporous structures. This changes the membrane's mechanical properties and gas-polymer interaction characteristics, enhancing plasticization resistance through the rigid crosslinked network and microporous architecture that resist CO2-induced swelling.
3Productivity
If blended polymer membranes are prepared to increase transport properties, then permeability is improved, but selectivity decreases and plasticization increases
Solution Approach 1:
The patent employs crosslinked PIM polymers with controlled microporous structures that provide size-sieving capabilities. The hierarchical pore architecture enables selective CO2 transport through microporous pathways while blocking larger molecules, maintaining high selectivity despite the blended polymer composition and enhanced permeability.
Solution Approach 2:
The patent creates local microporous regions within the blended membrane where crosslinked PIM domains are concentrated. These localized microporous zones provide selective transport pathways for CO2, ensuring that the blended membrane maintains high selectivity in specific regions while achieving overall enhanced permeability through the distributed microporous network.
4Measurement precision
If amine absorption technology is used for acid gas removal, then removal efficiency is improved, but energy consumption and capital cost increase
Solution Approach 1:
The patent replaces the thermal-based amine absorption process with a membrane-based separation system that operates at ambient conditions. The membrane utilizes size-sieving effects, adsorption mechanisms, and microporous transport pathways to achieve CO2 removal without requiring heat input for regeneration, dramatically reducing energy consumption while maintaining high removal efficiency.
Solution Approach 2:
The patent extracts the CO2 separation function from the bulk liquid amine absorption system and implements it in a thin-film membrane structure. This extraction enables selective CO2 transport through the membrane's microporous pathways and selective permeation mechanisms, achieving efficient acid gas removal with minimal energy input and simplified process equipment.
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 exhibit increased CO2 permeability by 10-100% and CO2/CH4 selectivity by 10-100%, along with improved plasticization resistance up to 800 psi CO2 feed pressure, surpassing the performance of traditional polyimide-based membranes.
Implementation Method 1
thermal crosslinking via nitrene reaction
Implementation Method 2
gas separation applications, such as removal of CO2 from natural gas
Implementation Method 3
enhanced CO2 permeability
Data Source
AI summary
This disclosure relates to blended polymeric membranes containing a polyimide polymeric matrix blended with a crosslinked polymer of intrinsic microporosity and methods of using the membranes for gas separation applications, such as removal of CO2 from natural gas.