Radon Separation from CO2 via Isobaric Thermal Adsorption
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Solution Overview
Problem
Current methods for separating Radon from carbon dioxide mixtures, such as distillation and adsorption using active carbon, are inefficient due to similar boiling points and binding properties, leading to incomplete separation and radioactive contamination risks, especially when dealing with high Radon concentrations.
Innovation Solution
An isobaric process utilizing an active carbon substrate from coconut shells, with adsorption and desorption cycles at atmospheric pressure, involving a thermal cycle with adsorption, heating, cooling, and washing phases to efficiently separate Radon from carbon dioxide without depressurization, using a system with multiple separation units for continuous operation and reduced radioactive waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to separate Radon from carbon dioxide, then separation is attempted, but the process fails due to extreme similarity of boiling points
Solution Approach 1:
The patent changes the separation mechanism from thermal (distillation based on boiling point differences) to adsorptive (based on molecular size and polarity interactions with active carbon). This parameter change in the separation mechanism allows effective separation despite similar boiling points, as Radon's larger molecular diameter (417-460 pm vs 330-361 pm for CO2) and non-polar characteristics enable selective adsorption on active carbon substrate.
Solution Approach 2:
The patent employs active carbon, a porous material with high surface area and specific adsorption properties. The porous structure of active carbon provides numerous adsorption sites that selectively interact with Radon molecules based on their size and polarity, enabling separation from carbon dioxide that cannot be achieved through distillation due to similar boiling points.
2Manufacturing precision
If active carbon adsorption is used to separate Radon from carbon dioxide, then adsorption occurs, but CO2 competes for binding sites reducing separation effectiveness
Solution Approach 1:
The patent implements periodic action through cyclic regeneration of the active carbon substrate. The process alternates between adsorption phase (where Radon is captured from CO2 stream) and regeneration phase (where accumulated Radon is desorbed by heating the carbon). This periodic operation allows the substrate to maintain high adsorption capacity continuously, preventing CO2 breakthrough and ensuring consistent separation efficiency despite competitive adsorption.
Solution Approach 2:
The patent changes the physical parameter of the active carbon substrate by applying thermal energy during regeneration. Heating the carbon substrate increases the kinetic energy of adsorbed Radon molecules, overcoming the adsorption forces and causing desorption. This parameter change (temperature increase) allows periodic restoration of the substrate's adsorption capacity, maintaining separation effectiveness over time.
3Object-affected harmful factors
If Radon is allowed to decay for more than 40 days to eliminate it, then radioactivity is reduced, but the technique is not applicable for most products
Solution Approach 1:
The patent extracts Radon from the carbon dioxide stream using active carbon adsorption, removing the harmful radioactive component before the CO2 is used or stored. This extraction approach eliminates the need for long-term storage or decay periods, making the process applicable to most products including those that cannot be stored for 40+ days. The Radon is concentrated on the carbon substrate which can then be regenerated or disposed of separately.
Solution Approach 2:
The patent replaces the passive temporal solution (waiting 40 days for radioactive decay) with an active mechanical/chemical separation system (active carbon adsorption). This substitution transforms the problem from one requiring time-based mitigation to one solved by immediate physical separation, dramatically improving productivity and broadening applicability to products that cannot undergo long storage periods.
4Manufacturing precision
If vacuum swing adsorption is used to separate Radon from air or nitrogen, then separation is achieved, but the technique requires constant pressure cycling and is limited to specific applications
Solution Approach 1:
The patent changes the regeneration parameter from pressure-based (VSA) to temperature-based (TSA). Instead of cycling between high and low pressure to desorb Radon, the system uses temperature cycling: adsorption occurs at ambient or low temperature, and regeneration is achieved by heating the carbon substrate to desorb the accumulated Radon. This parameter change simplifies the equipment requirements, eliminating the need for complex pressure cycling systems while maintaining separation efficiency.
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 allows for effective and safe separation of Radon from carbon dioxide at atmospheric pressure, reducing radioactive contamination and energy costs, enabling the treatment of both low and high Radon concentrations while minimizing the production of radioactive waste and ensuring product safety.
Implementation Method 1
adsorption of Radon from the mixture of raw gases on an active carbon substrate produced from coconut shell
Implementation Method 2
desorption of Radon from the substrate, and, following removal with a washing fluid, recovery of the substrate
Implementation Method 3
heating that goes on until a certain temperature T3 of about 120°C to about 180°C is reached
Data Source
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AI summary
A process for the separation of Radon from a mixture of gases consisting mainly of Carbon dioxide includes adsorption (ad) of the Radon present in the mixture of gases in a substrate (8) and simultaneous removal of Carbon dioxide, and desorption (de) of Radon from the substrate (8), followed by the removal of Radon through a washing fluid (Gi) and recovery of the substrate (8). The process happenswith, substantially,no pressurisation and/or depressurisation ofthe substrate (8) in a thermal cycle including an adsorption (ad) phase, a heating (ri) phase and a cooling (ra) phase. A respectiveplant having three separation units (1, 2, 3), a high-temperature heat source (4) anda low-temperature heat absorber (5), a counter-current heat exchanger (6) and tubes (7) for their connection.