Aqueous Carboxylic Acid Salt Solvent for Low-Energy CO2 Capture
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Solution Overview
Problem
Current carbon dioxide capture technologies, particularly those using amine-based solvents, are energy-intensive, costly, and face challenges with large volumes of flue gas, leading to high energy consumption and equipment degradation, making them inefficient for large-scale applications like power plants.
Innovation Solution
A method utilizing an aqueous composition with metal salts of aliphatic carboxylic acids and non-aqueous solvents, where the solvent composition is manipulated to control pKa values, allowing for efficient CO2 capture and release at ambient temperatures, reducing energy requirements and minimizing solvent degradation and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If amine-based solvents are used for CO2 capture, then CO2 absorption efficiency is improved, but energy consumption increases significantly
Solution Approach 1:
The patent changes the chemical parameters of the absorption medium by using phase transfer catalysts (quaternary ammonium salts, phosphonium salts, or sulfonium salts) combined with carboxylic acid salts to fundamentally alter the reaction mechanism. This enables CO2 absorption at ambient temperature without requiring the high energy input needed for conventional amine-based systems, while maintaining high absorption efficiency through enhanced interfacial mass transfer.
Solution Approach 2:
The patent introduces phase transfer catalysts as intermediary substances that facilitate the interaction between CO2 and carboxylic acid salts. These catalysts act as mediators that enhance the absorption process by improving mass transfer across phases, enabling efficient CO2 capture without the energy-intensive conditions required by direct amine-CO2 reactions.
2Quantity of substance
If amine-based solvents are used for CO2 capture, then CO2 absorption capacity is improved, but solvent degradation occurs
Solution Approach 1:
The patent changes the chemical nature of the absorption system by replacing amine-based solvents with carboxylic acid salt systems activated by phase transfer catalysts. This fundamental parameter change eliminates the degradation issues inherent in amine systems while maintaining high CO2 absorption capacity through catalytically enhanced reaction kinetics and equilibrium.
Solution Approach 2:
The patent employs carboxylic acid salts that can be readily regenerated and reused, replacing the need for expensive, degradation-prone amine solvents. The system uses catalysts that remain stable and active over multiple cycles, effectively creating a durable, reusable absorption system that avoids the solvent replacement costs associated with amine degradation.
3Productivity
If thermal stripping is used for solvent regeneration, then CO2 release is achieved, but energy consumption increases
Solution Approach 1:
The patent fundamentally changes the regeneration mechanism by eliminating thermal stripping entirely. Instead, the system uses phase transfer catalysts that enable CO2 release through simple filtration or phase separation at ambient temperature. This parameter change from thermal to mechanical/chemical separation reduces energy consumption while maintaining efficient CO2 release rates.
Solution Approach 2:
The patent replaces the thermal field (heat-based stripping) with a mechanical/chemical field approach using phase transfer catalysis and filtration. This substitution eliminates the need for high-temperature heating while achieving equivalent or superior CO2 release efficiency through catalytically enhanced mass transfer and simple phase separation.
4Productivity
If conventional absorption equipment is used, then CO2 capture is achieved, but equipment complexity increases
Solution Approach 1:
The patent changes the operational parameters of the absorption process by enabling it to proceed at ambient temperature and pressure with simplified equipment. The use of phase transfer catalysts allows the system to achieve high capture rates without complex heat exchangers, steam strippers, or temperature control systems, reducing equipment complexity while maintaining productivity.
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 CO2 capture and release with significantly lower energy consumption and reduced environmental impact, making it suitable for large-scale industrial applications such as power stations and other acid gas-producing processes.
Implementation Method 1
a method for the capture of carbon dioxide from a gas stream by contact with an aqueous composition comprising at least one metal salt of an aliphatic carboxylic acid and at least one non-aqueous solvent
Implementation Method 2
the pKa of the carboxylic acid is significantly different in the aqueous non-aqueous solvent mixture than in water alone, allowing for efficient CO2 capture
Implementation Method 3
the pKa of the carboxylic acid is significantly different in the aqueous non-aqueous solvent mixture than in water alone
Data Source
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AI summary
The invention provides the use of an aqueous composition comprising at least one metal salt of an aliphatic carboxylic acid and at least one water-miscible non-aqueous solvent for the capture and release of CO2; wherein said at least one metal salt of an aliphatic carboxylic acid is initially present in said composition at a level of between 1M and 14M. The method offers a convenient and simple process which uses inexpensive consumables and offers significant advantages over the methods of the prior art.