Membrane and PSA Integration for CO2 Recovery
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Solution Overview
Problem
Current carbon dioxide separation technologies, such as aqueous amine systems and membrane separation, are energy inefficient, costly, and not suitable for offshore use due to high energy requirements, complexity, and the need for multiple stages, while pressure swing adsorption (PSA) is not effectively applied to natural gas processing for high-volume applications.
Innovation Solution
Integration of membrane-based separation units with pressure swing adsorption (PSA) units, along with hydrogen sulfide polishing units, to enhance carbon dioxide recovery by processing inlet gas streams, reducing hydrogen sulfide concentrations, and achieving high purity carbon dioxide and methane streams in a single-pass system without the need for additional heat regeneration or complex equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous amine systems are used for carbon dioxide separation, then carbon dioxide removal is achieved, but energy consumption increases and equipment complexity increases
Solution Approach 1:
The patent replaces the thermal regeneration system (mechanical/thermal) with a pressure-swing-based system. The PSA unit uses pressure variations instead of high-temperature heating to regenerate the adsorbent, thereby removing the need for reboilers and high-energy thermal cycles while maintaining effective CO2 removal.
Solution Approach 2:
The patent changes the operating parameter from temperature-based regeneration (aqueous amine requiring 120-140°C) to pressure-based regeneration (PSA operating at variable pressures). This parameter change enables lower energy consumption while achieving the same separation objective.
2Reliability
If aqueous amine systems are used for carbon dioxide separation, then carbon dioxide removal is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the complex thermal regeneration subsystem (reboilers, condensers, high-temperature heat exchangers) from the separation system. By using PSA, only pressure control valves and adsorption beds are needed, significantly simplifying the equipment architecture while maintaining separation effectiveness.
Solution Approach 2:
The patent substitutes the complex thermal field equipment (reboilers, steam generation systems) with a simpler pressure-controlled adsorption system. This mechanical substitution reduces equipment complexity while achieving the same CO2 removal function.
3Area of stationary object
If membrane separation is used for carbon dioxide removal, then equipment footprint is reduced, but product purity decreases and additional stages are required
Solution Approach 1:
The patent merges the membrane separation unit with a PSA unit in series. The membrane provides initial CO2 removal in a compact footprint, and the PSA unit polishes the gas stream to achieve high purity. This combination achieves both compact size and high product purity that neither system could achieve alone.
Solution Approach 2:
The membrane separation performs preliminary CO2 removal, concentrating the CO2 in the permeate stream. This preliminary action reduces the load on the subsequent PSA unit, enabling it to achieve high purity more efficiently and justifying the compact overall footprint.
4Loss of substance
If membrane separation with recycle stream is used to enhance product recovery, then carbon dioxide recovery is improved, but energy consumption increases and device complexity increases
Solution Approach 1:
The patent replaces the energy-intensive compression and recycle system with a pressure-swing adsorption system. The PSA unit achieves enhanced CO2 recovery through pressure variations without requiring continuous compression of recycle streams, thereby reducing energy consumption while maintaining high recovery rates.
5Use of energy by moving object
If pressure swing adsorption is applied to natural gas processing, then energy efficiency improves and equipment complexity reduces, but application to high-volume natural gas processing is limited
Solution Approach 1:
The patent combines membrane separation (suitable for high-volume processing) with PSA (energy-efficient and simple). The membrane handles the bulk high-volume separation, while the PSA unit processes the concentrated permeate stream. This merging enables PSA to be effectively applied to high-volume natural gas processing while retaining its energy efficiency advantages.
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 integrated system achieves efficient and economic carbon dioxide recovery with high purity, reducing energy consumption and equipment complexity, and allows for the recovery of valuable products like methane and carbon dioxide from waste streams, transforming them into saleable products.
Implementation Method 1
introducing the outlet gas stream to one or more membrane-based separation units, operating the one or more membrane-based separation units to produce a permeate byproduct gas stream having increased concentration of carbon dioxide
Implementation Method 2
introducing the permeate byproduct gas stream to one or more pressure swing adsorption units, and operating the one or more pressure swing adsorption units to produce a substantially pure carbon dioxide stream
Implementation Method 3
introducing the inlet gas stream, having carbon dioxide and hydrogen sulfide, to one or more hydrogen sulfide polishing units and operating the one or more hydrogen sulfide polishing units to produce an outlet gas stream with a reduced concentration of hydrogen sulfide
Data Source
AI summary
Methods and systems of enhanced carbon dioxide recovery from an inlet gas stream are provided, by introducing the gas stream to one or more membrane-based separation units to produce a permeate byproduct gas stream having increased concentration of carbon dioxide compared to the inlet gas stream and then introducing the permeate byproduct gas stream to one or more pressure swing adsorption units or trains to enhance recovery of hydrocarbons, such as methane, lost in the byproduct stream and to produce a substantially pure carbon dioxide stream, while minimizing process compression and eliminating process heat for process regeneration. The methods introduced herein are for enhancing product recovery by enhancing carbon dioxide recovery from gas streams with pressures greater than atmospheric conditions. Further refinement to the methods would be the introduction of hydrogen sulfide polishing units within the process to produce product that meets or exceeds sales quality specifications.