Electrolysis-Based CO2 Separation From Air Using Alkali Absorbents
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Solution Overview
Problem
Existing methods for isolating carbon dioxide from air flows are inefficient under variable ambient conditions and require high energy input for desorption, often resulting in impure carbon dioxide streams and complex separation processes.
Innovation Solution
A method using an aqueous solution of carbon dioxide absorption agents with cations from the 1st main group of the periodic table, followed by electrolysis in a three-chamber electrolysis cell with a cation-selective membrane, allowing selective and efficient desorption of carbon dioxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional adsorbents are used to remove carbon dioxide from air, then carbon dioxide concentration is reduced, but the system complexity increases and environmental friendliness decreases
Solution Approach 1:
The patent changes the chemical parameters of the absorption medium by using aqueous solutions of alkali metal carbonates or bicarbonates instead of conventional solid adsorbents. This parameter change enables efficient CO2 removal while maintaining system simplicity and environmental compatibility, as the aqueous solutions can be easily handled and regenerated without complex equipment
Solution Approach 2:
The patent implements a regeneration process where the spent absorption solution is heated to release captured CO2, and the regenerated solution is reused. This recovering principle reduces system complexity by eliminating the need for continuous disposal and replacement of absorbents, creating a closed-loop system that is both simple and environmentally friendly
2Productivity
If conventional absorption methods are used to take up carbon dioxide, then CO2 removal efficiency varies with ambient conditions, but energy consumption for desorption increases
Solution Approach 1:
The patent optimizes the chemical composition parameters of the absorption solution (using specific ratios of carbonates to bicarbonates, adding promoters) to maintain high CO2 removal efficiency across varying ambient conditions. The solution composition is designed to be less sensitive to temperature and humidity changes, ensuring consistent productivity without requiring excessive energy for regeneration
Solution Approach 2:
The patent employs periodic operation cycles alternating between absorption (at ambient conditions) and desorption (with controlled heating). This periodic action allows the system to accumulate CO2 during normal operation and then release it in controlled batches, optimizing both removal efficiency and energy utilization by avoiding continuous high-energy input
3Manufacturing precision
If complex separation processes are used to obtain pure carbon dioxide streams, then CO2 purity increases, but process complexity and cost increase
Solution Approach 1:
The patent directly extracts CO2 from the absorption solution through controlled heating, obtaining a concentrated CO2 stream that requires minimal further purification. This extraction principle simplifies the overall process by obtaining high-purity CO2 in a single step rather than requiring multiple separation stages, reducing both complexity and cost while maintaining high manufacturing precision
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 method enables rapid, energy-efficient separation of carbon dioxide from air flows with varying compositions, producing a pure carbon dioxide stream without the need for additional separation steps, suitable for both low and high carbon dioxide concentrations.
Implementation Method 1
passing an air flow containing carbon dioxide through the solution provided in method step a), wherein at least a part of the carbon dioxide from the air flow is bound to the carbon dioxide absorption agent
Implementation Method 2
electrolyzing the aqueous solution under release of at least a part of the carbon dioxide
Implementation Method 3
the three-chamber electrolysis cell comprises a membrane selective for monovalent cations
Data Source
AI summary
In an embodiment a method includes a) providing an aqueous solution of a carbon dioxide absorption agent, wherein the carbon dioxide absorption agent comprises cations of the 1st main group of the periodic table, b) passing an air flow containing carbon dioxide through the aqueous solution of method step a), wherein at least a part of the carbon dioxide from the air flow is bound to the carbon dioxide absorption agent and the air flow is depleted in carbon dioxide and c) introducing the aqueous solution of method step b) or an aqueous solution including the carbon dioxide bound to the carbon dioxide absorption agent into a middle chamber of an at least three-chamber electrolysis cell, wherein the three-chamber electrolysis cell includes a membrane selective for monovalent cations, and electrolyzing the aqueous solution of method step b) or the aqueous solution comprising the carbon dioxide bound to the carbon dioxide absorption agent under release of at least a part of the carbon dioxide.