Electrochemical Cell for Selective CO2 Capture from Low Concentration Streams
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Solution Overview
Problem
Conventional methods for capturing target gases like carbon dioxide from low-concentration streams, such as ambient air or ventilated air, are energy-intensive and inefficient, particularly when oxygen is present in high concentrations, as they often react with electroactive species, reducing capture efficiency.
Innovation Solution
The development of electrochemical cells with specific electroactive species, such as quinones, that remain thermodynamically unfavorable for reaction with oxygen across a range of temperatures, allowing for selective capture and release of carbon dioxide with minimal oxygen removal, using a process involving potential differences and conductive liquids to facilitate bonding and release of CO2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal methods are used to capture carbon dioxide from low-concentration streams, then carbon dioxide can be captured, but the process becomes energy-intensive and inefficient
Solution Approach 1:
The patent replaces thermal methods (heat-based separation) with electrochemical methods. The electrochemical cell uses electrical potential to drive redox reactions of electroactive species, enabling CO2 capture at lower temperatures and with reduced energy consumption compared to conventional thermal swing adsorption or membrane separation processes.
Solution Approach 2:
The patent changes the operating parameters from high-temperature thermal processes to ambient or moderate temperature electrochemical processes. By controlling electrical potential and using redox-active species, the system achieves effective CO2 capture from low-concentration streams without the high energy input required by thermal methods.
2Reliability
If electroactive species are used to capture carbon dioxide, then capture efficiency improves, but oxygen present in high concentrations reacts with the electroactive species, reducing capture efficiency
Solution Approach 1:
The patent applies local quality by creating different chemical environments at different electrodes. The negative electrode is designed with electroactive species that have high affinity for CO2 under reducing conditions, while the positive electrode provides oxidizing conditions. This spatial differentiation allows selective CO2 capture at the negative electrode while oxygen reduction occurs at the positive electrode, minimizing oxygen interference with CO2 capture.
Solution Approach 2:
The patent uses the electrochemical cell and external power source as intermediaries to control the redox state of electroactive species. By applying appropriate potentials, the system maintains electroactive species in a reduced state that selectively binds CO2, while the circuit configuration ensures oxygen reacts at the positive electrode rather than competing for the electroactive species at the negative electrode.
3Reliability
If conventional gas separation methods are used, then separation can be achieved, but the process becomes complex and costly
Solution Approach 1:
The patent makes the electrochemical cell multi-functional by combining CO2 capture, oxygen removal, and potential CO2 conversion in a single device. The electroactive species serve multiple roles: binding CO2 when reduced, releasing CO2 when oxidized, and the system can potentially convert CO2 to other chemicals. This eliminates the need for separate capture, separation, and processing units required by conventional methods.
Solution Approach 2:
The patent merges multiple gas separation functions into a single electrochemical cell. Instead of using separate stages for CO2 capture, oxygen removal, and gas drying, the electrochemical system performs these functions simultaneously through controlled redox reactions, simplifying the overall process architecture and reducing equipment complexity.
4Reliability
If electrochemical cells are designed for high CO2 concentration streams, then capture efficiency is high, but the cells are not effective for low-concentration streams like ambient air
Solution Approach 1:
The patent introduces dynamics by using electrochemically controlled redox reactions that can be rapidly switched between capturing and releasing states. The electroactive species can dynamically adjust their binding affinity for CO2 based on applied potential, allowing the system to effectively operate across a wide range of CO2 concentrations by modulating the electrochemical driving force rather than being fixed for a specific concentration range.
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 enables efficient and energy-efficient capture of carbon dioxide from low-concentration streams with minimal oxygen interference, improving the productivity and cost-effectiveness of gas separation systems.
Implementation Method 1
the first electroactive species has an oxidized state and at least one reduced state in which the species is capable of bonding with a target gas
Implementation Method 2
the species is capable of bonding with a target gas
Data Source
AI summary
Methods, apparatuses, and systems related to the electrochemical separation of target gases from gas mixtures are provided. In some cases, a target gas such as carbon dioxide is captured and optionally released using an electrochemical cell (e.g., by bonding to an electroactive species in a reduced state). Some embodiments are particularly useful for selectively capturing the target gas while reacting with little to no oxygen gas that may be present in the gas mixture. Some such embodiments may be useful in applications involving separations from gas mixtures having relatively low concentrations of the target gas, such as direct air capture and ventilated air treatment.