Calcium Sorbent Coatings for Passive Direct Air CO2 Capture
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Solution Overview
Problem
Current methods for capturing carbon dioxide from ambient air are costly and inefficient due to the high capital and operating expenses associated with regenerable solvents and chemicals, and the need for active air flow, making them unsuitable for large-scale implementation.
Innovation Solution
A passive calcium sorbent system with a high surface area configuration, utilizing thin layers of calcium hydroxide on substrates, which allows for spontaneous carbonation without the need for regenerable chemicals or forced air, thereby reducing costs and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If regenerable solvents and chemicals are used for CO2 capture, then capture efficiency is improved, but capital and operating costs increase
Solution Approach 1:
The patent uses inexpensive, non-regenerable calcium-based sorbents (such as calcium hydroxide, calcium oxide, or calcium carbonate) that are replaced periodically rather than regenerated. These sorbents are applied as thin coatings on substrates or as packed bed materials, capturing CO2 through chemical reaction to form calcium carbonate. The low cost of these materials and their simplicity eliminate the need for expensive regeneration systems while maintaining effective CO2 capture.
Solution Approach 2:
The patent extracts the CO2 capture function from complex regenerable solvent systems and implements it through simple calcium-based sorbent materials. By removing the regeneration requirement and using straightforward chemical absorption with calcium compounds, the system achieves cost reduction while preserving capture efficiency.
2Productivity
If active air flow systems are used, then CO2 removal rate is improved, but energy consumption and equipment complexity increase
Solution Approach 1:
The patent employs passive air flow systems where natural convection and diffusion drive air through the sorbent beds without requiring active fans or pumps. The thin-layer sorbent configurations and packed bed structures are designed to allow ambient air to flow through naturally, enabling CO2 capture through passive chemical absorption. This eliminates energy consumption associated with forced air circulation while maintaining effective removal rates.
3Area of moving object
If thin layers of sorbent are used, then surface area is maximized for capture efficiency, but sorbent loading capacity decreases
Solution Approach 1:
The patent transitions from bulk sorbent materials to thin-layer coatings applied on substrates (such as sheets, tubes, or structured surfaces). This dimensional transformation dramatically increases the surface area to volume ratio, allowing much greater CO2 capture capacity per unit mass of sorbent. The thin layers are applied through coating techniques and are supported by structural substrates that provide mechanical strength while enabling high surface area exposure to ambient air.
4Productivity
If high specificity is required for dilute CO2 in air, then capture efficiency is improved, but system complexity and cost increase
Solution Approach 1:
The patent changes the chemical parameters of the sorbent material to calcium-based compounds that have high affinity for CO2 at ambient concentrations. These materials are selected and configured (as thin layers or packed beds) to optimize their interaction with dilute CO2 in air, achieving high capture efficiency through material selection and structural design rather than through complex separation equipment or multiple processing stages.
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 achieves efficient carbon dioxide capture at a lower cost by maximizing sorbent surface area and minimizing equipment requirements, enabling practical implementation at an industrial scale.
Implementation Method 1
capture carbon dioxide directly from air or another stream through use of a sorbent
Implementation Method 2
accelerate carbonation of a calcium sorbent in ambient air
Data Source
AI summary
Systems and methods for direct air capture of carbon dioxide or other gases utilize a calcium sorbent in a manner that allows for wide scale, relatively low cost implementation. In particular, a calcium sorbent may be provided as a substantially thin coating on one or more substrates and utilized for direct air capture of carbon dioxide through chemisorption. The carbonated sorbent may be disposed of for sequestration of the carbon dioxide or regenerated with capture of carbon dioxide released from the carbonated sorbent during the regeneration process.