Structured Adsorbent Contactor for PSA 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 are inefficient in removing impurities like CO2, H2S, and N2 from natural gas, which limits methane recovery and increases operational costs.
Innovation Solution
The development of an adsorbent contactor with a low volume fraction of mesopores and macropores, utilizing structured adsorbents with selectivity for specific gas components, and incorporating a blocking agent to minimize open pore volume, allowing for efficient separation and recovery of light components in swing adsorption processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional adsorbents with high porosity are used to achieve high surface area for adsorption, then adsorption capacity is improved, but mass transfer efficiency deteriorates due to diffusion limitations in micropores
Solution Approach 1:
The contactor is segmented into multiple parallel flow channels with adsorbent material coating the channel surfaces, creating multiple independent mass transfer pathways that reduce diffusion limitations while maintaining high adsorption capacity through the distributed microporous structure
Solution Approach 2:
The adsorbent material is applied as a coating layer on the internal surfaces of flow channels, creating a localized high-surface-area region that maximizes adsorption capacity at the gas-solid interface while the channel geometry provides favorable mass transfer characteristics
2Reliability
If high feed pressures are used to increase adsorption loading, then heavy component removal is improved, but light component recovery deteriorates due to competitive adsorption
Solution Approach 1:
The system dynamically switches between adsorption and desorption modes through pressure cycling, allowing the adsorbent to selectively adsorb heavy components during high-pressure adsorption phases and then release them during pressure reduction, while light components are recovered in the effluent stream
Solution Approach 2:
The process uses feedback control through monitoring of adsorbent loading and effluent composition to optimize pressure cycling parameters, adjusting operational conditions to maximize both heavy component removal and light component recovery
3Reliability
If conventional PSA processes are used to separate gas components, then heavy component separation is achieved, but light component recovery and purity are insufficient
Solution Approach 1:
The contactor divides the gas flow into multiple parallel channels with independent adsorbent coatings, allowing different regions to operate at different loading states and enabling simultaneous optimization of heavy component removal and light component recovery through distributed mass transfer
Solution Approach 2:
The invention utilizes microporous adsorbent materials with specific pore size distributions that provide molecular sieve characteristics, selectively allowing certain gas components to access the adsorption sites while blocking others based on their molecular dimensions
4Speed
If mesopores and macropores are increased to improve mass transfer, then diffusion rate is improved, but adsorption capacity deteriorates due to reduced micropore volume
Solution Approach 1:
The contactor design creates localized regions with different pore structures: the adsorbent coating material provides microporous high-capacity adsorption zones on channel surfaces, while the channel void spaces provide macroporous mass transfer pathways, optimizing both capacity and rate functions in different locations
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 solution enables recovery of greater than 80% of the light component, such as methane, with improved purity and reduced losses, even at high feed pressures, while minimizing the volume of mesopores and macropores to enhance separation efficiency and reduce operational costs.
Implementation Method 1
gas separation 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
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 3
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
Data Source
AI summary
The present invention relates to engineered structured adsorbent contactors for use in pressure swing adsorption and thermal swing adsorption processes. Preferably, the contactors contain engineered and substantially parallel flow channels wherein 20 volume percent or less of the open pore volume of the contactor, excluding the flow channels, is in the mesopore and macropore range.