Ionic Liquid CO2 Converter for Space Life Support
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Solution Overview
Problem
Current carbon dioxide conversion technologies for long-duration space missions are hindered by the weight and maintenance challenges of solid sorbents, radiation susceptibility, and low oxygen yield, particularly in environments like spacecraft and Mars where efficient CO2 conversion to oxygen is crucial for life support and propulsion.
Innovation Solution
A carbon dioxide conversion system utilizing a gas-liquid contactor-separator and electrochemical cell with ionic liquid storage, which enables efficient CO2 sorption, electrochemical conversion to oxygen and reduced carbon species, and regeneration at lower temperatures, improving oxygen yield and system robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid sorbents are used for CO2 removal, then CO2 can be removed from the cabin, but the system becomes heavy and cannot be replaced or serviced in space
Solution Approach 1:
The patent replaces solid sorbents with a liquid ionic liquid-based absorbent system that flows through the contactor. This hydraulic approach allows the absorbent to be pumped, regenerated, and recirculated, eliminating the need for heavy solid sorbent beds while maintaining CO2 removal capability.
Solution Approach 2:
The patent changes the physical state of the absorbent from solid to liquid (ionic liquid), and operates the regeneration process at lower temperatures compared to traditional solid sorbent systems. This parameter change enables the system to be more mass-efficient and suitable for space applications.
2Reliability
If high regeneration temperature is used for CO2 desorption, then CO2 can be desorbed for Sabatier reactor, but the system complexity increases and O2 yield is limited to 50%
Solution Approach 1:
The patent changes the regeneration temperature parameter from high temperature (required for solid sorbents) to lower temperature operation using electrochemical methods. This reduces the thermal management complexity and allows direct integration with the electrolysis system for oxygen production.
Solution Approach 2:
The patent extracts the CO2 from the ionic liquid phase into a gas phase using electrochemical reduction, separating the CO2 removal function from the thermal regeneration process. This allows independent optimization of CO2 capture and oxygen production.
3Reliability
If water exposure occurs to solid sorbents, then adsorbed water is difficult to remove, but this creates maintenance challenges in space
Solution Approach 1:
The patent uses a liquid ionic liquid system that flows continuously through the contactor and can be easily pumped and replaced. Water contamination does not permanently degrade the system as it would solid sorbents, since the liquid can be filtered, regenerated, or replaced through standard fluid handling operations.
4Productivity
If conventional CO2 conversion systems are used, then oxygen can be produced, but the maximum O2 yield is limited to 50%
Solution Approach 1:
The patent extracts CO2 from the ionic liquid using electrochemical reduction at the cathode, directly converting it to carbon products while releasing oxygen at the anode. This direct electrochemical pathway bypasses the 50% yield limitation of conventional thermal processes and enables complete conversion of CO2 to oxygen and useful carbon products.
Solution Approach 2:
The patent uses electrochemical oxidation at the anode to rapidly convert water or hydroxide to oxygen, achieving high oxygen production rates. This accelerated oxidation process, driven by electrical current, enables oxygen yields exceeding 50% by directly converting the CO2-derived protons to oxygen.
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 system increases the maximum possible oxygen yield from CO2 to 67% and reduces system mass and complexity, enabling more efficient oxygen production for life support and potential fuel generation in space and Martian environments.
Implementation Method 1
CO2 is removed from the cabin by adsorption to solid sorbents
Implementation Method 2
electrochemical cell downstream of the first gas-liquid contactor-separator
Implementation Method 3
gas-liquid contactor-separator
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
A carbon dioxide conversion system for an environment includes a first gas-liquid contactor-separator downstream of the environment; an electrochemical conversion cell downstream of the first gas-liquid contactor-separator; and a cleaned ionic liquid storage intermediate the first gas-liquid contactor-separator and the electrochemical conversion cell.