PVA CO2 Separation Membrane for Solid Oxide Fuel Cell Efficiency
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Solution Overview
Problem
The existing CO2 separation methods in solid oxide fuel cell systems are inefficient due to non-reactive CO2 in the recycle feed stream, which reduces the overall system efficiency, and current techniques such as solvents, sorbents, and cryogenics are complex and less effective for CO2 removal.
Innovation Solution
A carbon dioxide separation membrane structure using a base polymer of poly vinyl alcohol (PVA) with carriers like poly aniline, sulfosuccinic acid, diethylenetriamine, imidazole, benzimidazole, diethanolamine, and glycine, configured to operate between 80° C. to 150° C., is introduced, along with a method of forming this membrane involving polysulfone and polyvinyl pyrrolidone support and solvent extraction steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional CO2 separation methods (solvents, sorbents, cryogenics) are used, then CO2 removal is achieved, but system complexity and operational difficulty increase
Solution Approach 1:
The patent extracts only the essential CO2 separation function from complex conventional systems by using a membrane that directly separates CO2 from the fuel cell exhaust stream. The membrane active layer with carriers selectively transports CO2 while allowing other gases to pass, eliminating the need for complex solvent circulation, adsorption/desorption cycles, or cryogenic cooling systems.
Solution Approach 2:
The membrane acts as an intermediary between the fuel cell exhaust stream and the sweep gas stream. The carriers embedded in the membrane matrix serve as mediators that facilitate selective CO2 transport from the feed side to the sweep side, enabling separation without direct contact between the gas streams and complex separation equipment.
2Productivity
If CO2 is removed from recycle feed, then fuel cell efficiency improves, but separation process complexity increases
Solution Approach 1:
The patent uses a thin-film membrane structure with an active layer containing carriers embedded in a polymer matrix. This thin-film approach provides high separation efficiency in a compact form factor, allowing CO2 removal without requiring large, complex separation equipment. The membrane can be integrated directly into the fuel cell system architecture.
3Loss of energy
If membrane operation temperature is increased to 80-150°C, then CO2 separation performance improves, but membrane material stability becomes challenging
Solution Approach 1:
The patent changes the operational temperature parameter to 80-150°C, which optimizes CO2 separation performance by enhancing carrier-CO2 interaction kinetics and membrane permeability. The membrane materials (polyvinyl alcohol base polymer with cross-linking and stable carriers) are specifically selected to maintain structural integrity and chemical stability at this elevated temperature range.
Solution Approach 2:
The membrane employs a composite structure consisting of a polyvinyl alcohol base polymer matrix, cross-linking agents for structural stability, and thermally stable carriers (such as metal complexes or organic molecules). This composite formulation provides both the required CO2 separation performance at elevated temperatures and the necessary material stability to prevent degradation.
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 effectively separates CO2 from the fuel cell exhaust stream, improving fuel cell efficiency by recycling CO2-depleted fuel, increasing the SOFC stack's performance and reducing recycle blower power loading, while maintaining mechanical stability and controlled swelling.
Implementation Method 1
a carbon dioxide separation membrane comprising: a base polymer comprising poly vinyl alcohol (PVA); and a carrier selected from at least one of: poly aniline (PANI); sulfosuccinic acid; diethylenetriamine (DETA); imidazole; benzimidazole; diethanolamine (DEA)
Implementation Method 2
a carrier selected from at least one of: poly aniline (PANI); sulfosuccinic acid; diethylenetriamine (DETA); imidazole; benzimidazole; diethanolamine (DEA)
Data Source
AI summary
A carbon dioxide membrane structure, a method of making the same, and a carbon dioxide separator including the same. The membrane structure may include a carbon dioxide separation membrane containing PVA and a carrier, and a polysulfone-based support having an average pore size ranging from about 40 to about 90 μm.