Structured Adsorbent Contactors for High Recovery Gas Separation
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Solution Overview
Problem
Conventional pressure swing adsorption (PSA) processes struggle to achieve high recovery and purity of both light and heavy components, especially at high feed pressures, and fail to efficiently separate CO2, N2, and H2S from natural gas, which is critical for natural gas processing and other gas separations.
Innovation Solution
A swing adsorption process using structured adsorbent contactors with a low volume fraction of mesopores and macropores, specifically designed to enhance the recovery of light components by employing adsorbents like 8-ring zeolites and stannosilicates, which selectively adsorb CO2, N2, and H2S, while minimizing the adsorption of methane, allowing for high recovery rates of methane and other valuable components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional PSA processes use microporous adsorbent materials with large surface area, then gas adsorption capacity is improved, but light component recovery deteriorates at high feed pressures
Solution Approach 1:
The patent uses microporous adsorbent materials (zeolites, activated carbons, silica gels, aluminas) with specifically controlled pore structures to achieve selective adsorption of heavy components while minimizing light component uptake, resolving the contradiction between adsorption capacity and light component recovery
Solution Approach 2:
The patent changes operating parameters including feed pressure, temperature, and cycle time to optimize the balance between adsorption capacity and light component recovery, particularly by operating at controlled pressure ranges and using rapid cycle PSA to prevent excessive light component adsorption
2Manufacturing precision
If PSA processes use adsorbents with high affinity for heavy components, then separation selectivity is improved, but light component recovery deteriorates
Solution Approach 1:
The patent applies different adsorbent materials with specific local properties (zeolites for CO2 removal, activated carbons for N2 removal) to different stages or beds, creating localized high selectivity zones that prevent overall light component loss while achieving heavy component separation
Solution Approach 2:
The patent uses dynamic rapid cycle PSA operations where adsorption and desorption cycles are rapidly alternated, allowing the system to achieve high selectivity during brief adsorption phases while preventing light component saturation that would lead to recovery losses
3Manufacturing precision
If conventional PSA processes are used for CO2, N2, and H2S removal from natural gas, then heavy component separation is improved, but process economics deteriorate due to low light component recovery
Solution Approach 1:
The patent implements continuous rapid cycle PSA operations with multiple beds operating in sequence, ensuring continuous natural gas processing with high methane recovery (>80%), thereby maintaining process economics while achieving effective CO2, N2, and H2S removal
Solution Approach 2:
The patent optimizes operating parameters including pressure, temperature, and cycle frequency to maximize both heavy component separation efficiency and light component recovery, improving process economics by recovering valuable methane that would otherwise be lost in conventional PSA processes
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 greater than 80% recovery of light components, such as methane, and effectively separates CO2 and H2S from natural gas, improving process economics and reducing resource loss, even at high feed pressures.
Implementation Method 1
Gas separation is important in various industries and can typically be accomplished by flowing a mixture of gases over an adsorbent that preferentially adsorbs a more readily adsorbed component relative to a less readily adsorbed component of the mixture
Implementation Method 2
One of the more important gas separation techniques is pressure swing adsorption (PSA). PSA processes rely on the fact that under pressure gases tend to be adsorbed within the pore structure of the microporous adsorbent materials
Implementation Method 3
Another important gas separation technique is temperature swing adsorption (TSA). TSA processes also rely on the fact that under pressure gases tend to be adsorbed within the pore structure of the microporous adsorbent materials. When the temperature of the adsorbent is increased, the gas is released, or desorbed
Implementation Method 4
Different molecules can have different affinities for adsorption into the pore structure or open volume of the adsorbent. This provides one mechanism for the adsorbent to discriminate between different gasses. In addition to their affinity for different gases, zeolites and some types of activated carbons, called carbon molecular sieves, may utilize their molecular sieve characteristics to exclude or slow the diffusion of some gas molecules into their structure
Implementation Method 5
When the pressure is reduced, the gas is released, or desorbed. PSA processes can be used to separate gases in a mixture because different gases tend to fill the micropore or free volume of the adsorbent to different extents. When the bed reaches the end of its capacity to adsorb nitrogen, it can be regenerated by reducing the pressure, thereby releasing the adsorbed nitrogen
Data Source
AI summary
The present invention relates to the separation of one or more of CO2, N2, and H2S gas components from a gas mixture containing at least a second gas using a swing adsorption process unit. The adsorbent contactors of the swing adsorption process unit are engineered structured adsorbent contactors having a plurality of flow channels wherein 20 volume percent or less of the open pore volume of the contactors is in the mesopore and macropore range.