Lithium Ion-Exchanged Polymer-Bound Zeolite Adsorbent
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Solution Overview
Problem
Conventional oxygen separation materials for on-board oxygen generation systems (OBOGS) face limitations due to the use of clay binders, which reduce zeolite capacity and gas access, and require higher activation temperatures than the organic binders currently employed, leading to incomplete water removal and reduced performance.
Innovation Solution
A method involving ion exchange of sodium ions with lithium ions in a polymer-bound zeolite adsorbent, using an organic polymer binder stable at high temperatures, followed by thermal treatment and vacuum drying to enhance oxygen concentration and increase nitrogen adsorption capacity, while reducing the weight and size of the adsorbent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If clay binder is used to form 1 mm beads, then the adsorbent structure is formed, but the available zeolite capacity is reduced by dilution and gas access is reduced by fouling zeolite pores
Solution Approach 1:
The patent removes the clay binder from the adsorbent formulation entirely, extracting the harmful component that caused pore fouling and capacity reduction. The zeolite particles are bound using only organic binder, eliminating the clay-induced dilution and pore blocking effects while maintaining structural integrity through the organic binder matrix.
Solution Approach 2:
The patent changes the binder material parameter from clay to organic binder, fundamentally altering the binding mechanism. This parameter change eliminates the negative effects of clay on zeolite capacity and gas access, while the organic binder provides sufficient structural support without the harmful properties of clay.
2Ease of manufacture
If organic binder with tg in range of 210°C is used, then the adsorbent can be processed, but complete activation requires temperature of at least 340°C which is not achievable with current binder
Solution Approach 1:
The patent changes the glass transition temperature parameter of the organic binder to be at least 340°C, matching the activation temperature requirement. This parameter change allows the binder to maintain structural integrity during high-temperature activation processes (340-400°C) while still being processable at lower temperatures during manufacturing, resolving the contradiction between ease of manufacture and activation completeness.
3Ease of manufacture
If conventional organic binder is used, then the adsorbent can be formed, but the weight necessary to devote to oxygen separation material is increased
Solution Approach 1:
The patent changes the molecular weight and density parameters of the organic binder to create a lighter, more efficient binding matrix. The modified organic binder provides sufficient structural support and binding strength while reducing the overall weight of the adsorbent material, thereby reducing the weight necessary to devote to oxygen separation material.
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 method results in an adsorbent that is up to 28% more efficient in nitrogen adsorption capacity and capable of regeneration, with a weight reduction of up to two to three times compared to conventional systems, suitable for aerospace applications.
Implementation Method 1
an adsorbent is used in on-board oxygen generation system (OBOGS) applications to remove nitrogen from the air, thereby enriching oxygen concentration in the outlet stream
Implementation Method 2
at least 340° C. is required for complete water removal
Implementation Method 3
treating the calcined adsorbent with a lithium salt to yield a treated adsorbent
Data Source
AI summary
A high capacity adsorbent may be used for enriching oxygen concentration in an air stream. Such a high capacity adsorbent may be from about 2 to about 3 times lighter relative to the currently available technology. Furthermore, the high capacity adsorbent is readily capable of regeneration after deactivation by water vapor. Unlike current available immobilization technology in which clay binder was used to bind 13X zeolite and additional 10% organic binder was used to immobilize beads, the adsorbents of the present invention may be made using just an organic binder, thereby reducing pore spoilage caused by the clay binder. Further unlike conventional adsorbents, which may use sodium as its cation, the adsorbent of the present invention uses a lithium cation, thereby resulting in enhanced nitrogen adsorption performance.