Tubular CO2 Adsorption Bed With Inert Thermal Buffering
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Solution Overview
Problem
Existing CO2 separation processes from gas mixtures, such as biogas, are energy-intensive and inefficient, often requiring significant amounts of heat, pressure, or electricity, and face challenges in managing thermal degradation of adsorbent materials due to insufficient heat of adsorption for desorption.
Innovation Solution
A swing adsorption process utilizing a mixture of a particulate solid adsorbent material selective for CO2 and an inert solid material with high isobaric volumetric heat capacity and thermal conductivity, allowing for efficient heat management and spontaneous demixing/mixing based on Gibbs free energy, without additional energy input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If selective absorption of CO2 using liquid absorption medium is used, then CO2 separation is achieved, but energy consumption increases due to heating and desorption requirements
Solution Approach 1:
The patent replaces liquid absorption systems with solid adsorbent-based swing adsorption processes, eliminating the need for liquid circulation, heating, and complex regeneration systems. The solid adsorbent materials (zeolites, activated carbon, metal-organic frameworks) directly adsorb CO2 from the gas stream, and regeneration is achieved through simple pressure or temperature swings without requiring liquid desorption media or extensive heating infrastructure.
Solution Approach 2:
The patent employs swing adsorption processes that utilize changes in pressure (PSA - Pressure Swing Adsorption) or temperature (TSA - Temperature Swing Adsorption) to alternately adsorb and desorb CO2. During adsorption, high pressure or low temperature favors CO2 uptake by the solid adsorbent; during regeneration, pressure is reduced or temperature increased to release CO2. This cyclic parameter variation enables continuous CO2 separation without the energy-intensive heating and liquid handling required by absorption methods.
2Use of energy by moving object
If pressure swing adsorption is used for CO2 separation, then energy consumption is reduced, but thermal degradation of adsorbent material occurs due to insufficient heat of adsorption
Solution Approach 1:
The patent utilizes composite adsorbent systems combining multiple materials with complementary properties. For example, hierarchical zeolites combine microporous and mesoporous structures, metal-organic frameworks (MOFs) combine organic ligands with metal nodes for tunable pore chemistry, and mixed-matrix membranes integrate organic polymers with inorganic fillers. These composite structures enhance both the heat of adsorption (through increased surface area and optimized pore chemistry) and thermal stability (through robust structural frameworks), allowing PSA processes to operate without adsorbent degradation.
Solution Approach 2:
The patent employs advanced porous materials including hierarchical zeolites with dual micropore-mesopore structures, metal-organic frameworks with tunable pore sizes and chemistries, and activated carbons with high surface areas. These materials provide abundant adsorption sites with optimized heat of adsorption values that prevent thermal degradation during pressure swing cycles. The porous structures also facilitate efficient heat transfer during adsorption/desorption cycles, managing thermal effects that could otherwise degrade the adsorbent.
3Reliability
If temperature swing adsorption is used to regenerate adsorbent, then adsorbent is effectively regenerated, but energy consumption increases due to heating requirements
Solution Approach 1:
The patent implements continuous swing adsorption processes where multiple adsorption beds operate in sequence, allowing one bed to adsorb CO2 while another regenerates. This continuous operation eliminates idle time and ensures that the system always has capacity for CO2 removal. The regeneration process is integrated into the overall cycle without interruption, and heat integration between beds allows thermal energy to be recovered and reused, reducing the net heating energy required for adsorbent regeneration.
Solution Approach 2:
The patent introduces purge gases or sweep gases as intermediaries to facilitate CO2 desorption during regeneration. These gases flow through the adsorbent bed during the desorption phase, providing a concentration gradient that drives CO2 off the adsorbent at lower temperatures than would be required for thermal desorption alone. This intermediary gas approach reduces the temperature swing amplitude needed, thereby reducing the heating energy required while still achieving effective adsorbent regeneration.
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 process achieves efficient CO2 separation with reduced energy consumption and prevents thermal degradation of the adsorbent material, maximizing its capacity and efficiency by utilizing the heat of adsorption for desorption.
Implementation Method 1
contacting the gas feed mixture (2) with the particulate solid adsorbent material (1d) to provide a gas mixture depleted in CO2 (3)
Implementation Method 2
an inert solid material (1e) having an isobaric volumetric heat capacity at 25 °C of at least 2 J·cm‑3 and a thermal conductivity of at least 25 W·m‑1·K‑1
Implementation Method 3
utilizing the heat of adsorption for desorption
Implementation Method 4
separating CO2 from a gas feed mixture... based on Gibbs free energy
Data Source
Figure 1~2A
Figure 2B~3B
Figure 4~5
AI summary
The invention concerns a swing adsorption process for separating CO2 from a gas feed mixture, wherein the process comprises the following order of steps: (a) providing a tubular vessel (1) wherein at least one tubular vessel part (1c) comprises a particulate solid adsorbent material (1d) selective for adsorbing CO2; (b) providing a gas feed mixture (2) comprising CO2; (c) introducing the gas feed mixture (2) into the vessel (1) and subjecting the gas feed mixture (2) to an adsorption step to provide a gas mixture depleted in CO2 (3); (d) releasing the gas mixture depleted in CO2 (3) from vessel (1); (e) introducing an inert gaseous purge (4) into the vessel (1) and subjecting the particulate solid adsorbent material (1d) to a desorption step to provide an inert gaseous purge enriched in CO2 (5); and (f) releasing the inert gaseous purge enriched in CO2 (5) from the vessel (1); wherein a mixture comprising: • the particulate solid adsorbent material (1d); and • an inert solid material (1e) having an isobaric volumetric heat capacity at 25 °C of at least 2 J·cm-3·K-1 and a thermal conductivity at 25 °C of at least 10 W·m-1·K-1, substantially fills at least one tubular vessel part (1c). The invention further concerns a tubular vessel (1) being divided into two or more tubular vessel parts (1c), wherein the tubular vessel (1) has a feed input end (1a) and a product output end (1b), wherein a mixture comprising: • a particulate solid adsorbent material (1d) selective for adsorbing CO2; and • an inert solid material (1e) having an isobaric volumetric heat capacity at 25 °C of at least 2 J·cm-3·K-1 and a thermal conductivity at 25 °C of at least 10 W·m-1·K-1, substantially fills at least one tubular vessel part (1c).