Method for argon production via cold pressure swing adsorption
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Solution Overview
Problem
Current methods for purifying argon gas from cryogenic distillation are inefficient, requiring expensive catalysts, large distillation columns, and often result in low argon recovery and contamination risks due to thermal swings and vacuum regeneration in pressure swing adsorption processes.
Innovation Solution
A pressure swing adsorption system using oxygen-selective zeolite adsorbents at cold temperatures, specifically 4A zeolites and sodium exchanged chabazite, operates at temperatures from −186° C. to −20° C., with regeneration at pressures greater than ambient, reducing the need for vacuum and thermal regeneration, and minimizing carbon introduction into the cryogenic distillation column.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If temperature swing adsorption (TSA) is used to regenerate 4A zeolite, then oxygen can be desorbed from the adsorbent, but argon enters pores at faster rates and remains trapped, reducing oxygen working capacity
Solution Approach 1:
The patent changes the regeneration parameter from temperature-based (TSA) to pressure-based (PSA at elevated temperatures). By operating at temperatures above 100°C and pressures above atmospheric during regeneration, argon desorption is enhanced while preventing re-adsorption, thus maintaining both oxygen working capacity and argon purity
Solution Approach 2:
The patent implements periodic cycling between adsorption (at low temperature and pressure) and regeneration (at high temperature and pressure). This periodic action allows the adsorbent to alternately capture oxygen and release it, maintaining continuous operational capacity while ensuring purity through controlled cycle conditions
2Loss of energy
If vacuum pressure swing adsorption (VPSA) is used during regeneration, then oxygen can be desorbed, but the likelihood of contaminating the adsorbent with leaks to atmospheric gases increases
Solution Approach 1:
The patent inverts the conventional VPSA approach by using positive pressure during regeneration instead of vacuum. By pressurizing the system above atmospheric pressure during the regeneration phase, atmospheric gas leaks are prevented from entering the system, while oxygen desorption is still achieved through elevated temperature and pressure conditions
3Manufacturing precision
If carbon molecular sieves (CMS) are used in PSA at ambient temperatures, then argon purification can be achieved, but argon recovery is less than 40% unless power and capital intensive multi-train processes are employed
Solution Approach 1:
The patent changes the operating parameters from ambient temperature PSA with CMS to elevated temperature PSA with 4A zeolite. This parameter change enables high argon recovery (>90%) while maintaining high purity, eliminating the need for multi-train configurations and significantly improving productivity
4Manufacturing precision
If deoxo or getter methods are used to purify crude argon, then high purity argon can be achieved, but expensive metal catalysts/getters and on-site hydrogen are required with potential hazards of uncontrolled exothermic reaction
Solution Approach 1:
The patent replaces expensive, hazardous metal catalysts/getters with reusable 4A zeolite adsorbent that can be regenerated in-place. The zeolite acts as a disposable-like component in terms of regeneration (discarding impurities and restoring functionality) but is not actually consumed, eliminating the need for continuous replacement and reducing both cost and complexity
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
This approach enhances argon recovery, reduces equipment and energy requirements, minimizes waste streams, and achieves high argon purity without the need for filtration, thereby improving productivity and reducing operational costs.
Implementation Method 1
introducing the pressurized crude argon stream into a pressure swing adsorption apparatus containing an oxygen-selective zeolite adsorbent
Implementation Method 2
pressure swing adsorption at cold temperatures
Implementation Method 3
4A zeolites and sodium exchanged chabazite
Implementation Method 4
adsorbing at feed temperatures below −100° C. to restrict argon from entering 4A pores and avoid significant argon co-adsorption
Implementation Method 5
regenerating the oxygen-selective zeolite adsorbent at a pressure greater than prevailing ambient pressure
Data Source
AI summary
Methods and systems for purifying argon from a crude argon stream are disclosed, employing pressure swing adsorption at cold temperatures from −186° C. to −20° C.; more preferably from −150° C. to −50° C.; and most preferably from −130° C. to −80° C. with oxygen-selective zeolite adsorbent. In some embodiments, the oxygen-selective zeolite adsorbent is a 4A zeolite, a chabazite, or a combination thereof.