Hybrid Membrane PSA Oxygen Separator
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Solution Overview
Problem
Current methods for producing high purity oxygen (>98%) are economically infeasible due to the lack of highly oxygen-selective membrane materials and are bulky, energy demanding, with low oxygen recovery efficiencies, especially for ambient temperature gas separation processes.
Innovation Solution
A hybrid system combining a high-efficiency membrane for initial argon and nitrogen separation, followed by a pressure swing adsorption unit using a specifically formulated zeolite compound to achieve high purity oxygen, with optional recycle configurations to enhance efficiency and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional PSA systems are used to produce high purity oxygen (>98%), then oxygen purity is achieved, but the system becomes bulky and energy demanding
Solution Approach 1:
The system divides the gas separation process into two distinct stages: a membrane separation section that performs initial enrichment of oxygen and removal of argon and nitrogen, followed by a PSA section that further purifies the stream to >98% oxygen purity. This segmentation allows each component to be optimized for its specific function, reducing the overall size and energy consumption compared to using a single large PSA system.
Solution Approach 2:
The membrane separation unit performs preliminary enrichment of the oxygen stream before it enters the PSA unit. By pre-concentrating oxygen and removing bulk amounts of nitrogen and argon upstream, the PSA unit receives a pre-conditioned feed that requires less processing, thereby reducing its size and energy demands while still achieving the final high purity specification.
2Manufacturing precision
If conventional two-stage PSA systems are used for high purity oxygen production, then oxygen purity >98% is achieved, but plant size increases and oxygen recovery efficiency decreases
Solution Approach 1:
The system segments the separation process into membrane-based preliminary enrichment followed by PSA-based final purification. The membrane section handles bulk removal of nitrogen and argon, allowing the PSA section to focus only on fine purification to >98% oxygen. This division improves oxygen recovery efficiency by reducing the burden on the PSA unit and enabling better utilization of the feed stream.
Solution Approach 2:
The system changes the composition parameter of the feed stream to the PSA unit by using the membrane to pre-enrich oxygen and remove nitrogen and argon. This parameter change (from ambient air composition to oxygen-enriched, nitrogen-reduced composition) allows the PSA unit to operate more efficiently with smaller bed sizes and higher oxygen recovery rates.
3Manufacturing precision
If highly oxygen-selective membrane materials are developed, then high purity oxygen (>98%) can be produced directly, but currently such materials are unavailable making the process economically infeasible
Solution Approach 1:
The system uses the membrane unit as an intermediary device that performs preliminary oxygen enrichment and nitrogen/argon removal. This intermediary step creates a pre-conditioned stream that is then easily purified to >98% oxygen by the PSA unit using conventional, commercially available materials and processes, thereby achieving high purity oxygen in an economically feasible manner.
Data Source
AI summary
A portable, non-cryogenic, oxygen generation system capable of delivering oxygen gas at purities greater than 98% and flow rates of 15 L/min or more is described. The system consists of two major components. The first component is a high efficiency membrane capable of separating argon and a portion of the nitrogen content from air, yielding an oxygen-enriched permeate flow. This is then fed to the second component, a pressure swing adsorption (PSA) unit utilizing a commercially available, but specifically formulated zeolite compound to remove the remainder of the nitrogen from the flow. The system is a unique gas separation system that can operate at ambient temperatures, for producing high purity oxygen for various applications (medical, refining, chemical production, enhanced combustion, fuel cells, etc . . . ) and represents a significant advance compared to current technologies.