Alkali Hydroxide Carbon Capture and Electrolysis Regeneration
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Solution Overview
Problem
Existing carbon capture technologies, particularly those using liquid amine solvents and alkaline ion exchange membranes, face high costs, energy inefficiencies, and limitations in capturing CO2 from air with low enrichment.
Innovation Solution
A method and apparatus for carbon capture coupled with hydrogen production using an alkali metal hydroxide solution to capture CO2 across a wide concentration range, followed by electrolysis with a non-ionic diaphragm to regenerate the absorption solution and produce hydrogen and oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid amine solvent-based adsorption method is used, then carbon dioxide capture capability is improved, but regeneration energy consumption increases and operating costs increase
Solution Approach 1:
The patent changes the chemical composition parameters of the absorption solution from traditional liquid amine solvents to an alkaline solution containing NaOH, KOH, or their mixtures with specific concentrations (e.g., 1-5M NaOH). This parameter change enables the solution to be regenerated through electrolysis at lower energy consumption while maintaining effective CO2 capture capability.
Solution Approach 2:
The patent replaces the thermal regeneration process (heating to decompose carbamates) with an electrochemical regeneration process (electrolysis). Instead of using high-temperature heating to release CO2 from amine-carbamate complexes, the system uses electricity to directly decompose the carbonate/bicarbonate formed from CO2 absorption, significantly reducing energy consumption.
2Reliability
If liquid amine solvent-based adsorption method is used, then carbon dioxide capture capability is improved, but operating costs increase
Solution Approach 1:
The patent employs inexpensive alkaline solutions (NaOH, KOH) that can be easily replenished and regenerated through electrolysis. Instead of using expensive liquid amine solvents that require energy-intensive regeneration, the system uses cheap alkaline materials that can be continuously regenerated at lower cost, reducing overall operating expenses.
Solution Approach 2:
The system incorporates an integrated electrolysis unit that automatically regenerates the alkaline absorption solution on-site. The electrolysis cell decomposes the carbonate/bicarbonate in the spent solution to regenerate NaOH/KOH, creating a self-sustaining cycle that eliminates the need for external chemical supply chains and reduces operational costs.
3Adaptability or versatility
If airborne carbon dioxide capture technology using liquid alkaline solution is used, then carbon dioxide capture from air is enabled, but regeneration energy consumption increases
Solution Approach 1:
The patent replaces thermal decomposition processes with electrochemical electrolysis for regeneration. When CO2 from air is absorbed by the alkaline solution forming carbonates, the electrolysis cell uses electrical energy to directly decompose these carbonates back to CO2 and regenerate the alkaline solution, consuming significantly less energy than thermal methods.
4Measurement precision
If calcination of calcium carbonate is used for regeneration, then high-purity carbon dioxide is obtained, but energy consumption increases and equipment investment increases
Solution Approach 1:
The patent substitutes the calcination process (thermal decomposition at high temperatures) with electrochemical electrolysis. Instead of heating calcium carbonate to 900°C+ to produce CO2 and CaO, the system uses electricity to electrolyze the carbonate/bicarbonate solutions, producing CO2 at much lower temperatures and energy consumption while achieving comparable purity.
5Reliability
If ionic membrane is used in electrolysis process, then solution regeneration is achieved, but equipment costs increase
Solution Approach 1:
The patent replaces expensive ion-exchange membranes with inexpensive non-ionic porous diaphragms for the electrolysis cell. These porous diaphragms effectively separate the anode and cathode compartments while allowing ion transport, performing the same function as ionic membranes but at a fraction of the cost, making the overall system more economically viable.
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 capture of CO2 across a wide concentration range, reduces capture and hydrogen production costs, and facilitates the regeneration of the absorption solution, thereby improving the overall economic and environmental viability of carbon capture technologies.
Implementation Method 1
capturing low-concentration CO2 by using a solution of an alkali metal hydroxide
Implementation Method 2
carbon dioxide is combined with the alkali solution to form a carbonate solution
Implementation Method 3
performing electrolysis by using a non-ionic diaphragm as a diaphragm
Implementation Method 4
performing electrolysis by using the second portion of the low-concentration CO2 absorption solution as a catholyte solution, using the high-concentration CO2 absorption solution as an anolyte solution
Data Source
Figure 1
AI summary
Disclosed are a method and an apparatus for carbon capture coupled hydrogen production. The method includes: capturing low-concentration CO2 by a solution of an alkali metal hydroxide to obtain a low-concentration CO2 absorption solution; capturing high-concentration CO2 by a first portion of the low-concentration CO2 absorption solution to obtain a high-concentration CO2 absorption solution; and performing electrolysis by a second portion of the low-concentration CO2 absorption solution as a catholyte solution, using the high-concentration CO2 absorption solution as an anolyte, and using a non-ionic diaphragm as a diaphragm. According to the method, capture of CO2 in a wide concentration range can be realized; electrolysis is performed by a non-ionic diaphragm, to implement regeneration of an absorption solution coupled hydrogen production; capture costs of CO2 in a wide concentration range can be reduced; additional products of H2 and O2 can be obtained; and hydrogen production costs can be reduced.