Direct Air Capture With Continuous Sorbent Circulation
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Solution Overview
Problem
Current atmospheric carbon capture technologies are inefficient and costly, limiting the ability to effectively reduce greenhouse gas concentrations in the atmosphere, particularly at locations other than point sources.
Innovation Solution
A continuous direct air capture system that uses a sorbent to adsorb and desorb CO2 without ceasing operation, employing a gravity-flow packed bed and a separate desorber to continuously move the sorbent through the system, allowing multiple cycles of adsorption and desorption without stoppages, and utilizing a free-standing bulk solid sorbent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch process (adsorption followed by desorption) is used, then CO2 removal is achieved, but system operation stops during process transitions
Solution Approach 1:
The system divides the sorbent into multiple beds (first adsorption bed, second adsorption bed, desorption bed) that operate in parallel segments. While one bed is undergoing desorption, another bed continues adsorption, eliminating system stoppages and maintaining continuous CO2 removal productivity.
Solution Approach 2:
The system implements continuous operation by maintaining adsorption activity in at least one bed at all times. The sorbent is continuously circulated between adsorption and desorption states through multiple parallel beds, ensuring uninterrupted CO2 removal from the atmosphere.
2Adaptability or versatility
If atmospheric CO2 concentration is low, then direct air capture is applicable, but CO2 capture efficiency decreases
Solution Approach 1:
The system employs sorbent material with optimized porous structure and surface chemistry to enhance CO2 adsorption capacity and selectivity. The porous material increases the effective surface area for CO2 capture, improving efficiency despite the low concentration of CO2 in atmospheric air.
Solution Approach 2:
The system optimizes operating parameters including temperature, pressure, and sorbent circulation rate to maximize CO2 capture efficiency from atmospheric air. By adjusting these parameters, the system maintains high productivity despite the challenging low CO2 concentration environment.
3Productivity
If sorbent is moved continuously through the system, then CO2 removal is uninterrupted, but system complexity increases
Solution Approach 1:
The system uses multiple discrete sorbent beds that can be independently operated and managed. This segmentation allows continuous CO2 removal through parallel operation while simplifying the overall system architecture compared to a single complex continuous flow system.
Solution Approach 2:
The sorbent material serves multiple functions: adsorbing CO2 during the adsorption phase, being regenerated during desorption, and circulating between beds. This multi-functionality reduces the need for separate specialized components, thereby managing system complexity while maintaining continuous operation.
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 provides a robust, economical solution for removing CO2 from the atmosphere at lower concentrations, enabling significant CO2 removal over time and contributing to mitigating climate change, with the potential to operate for extended periods without external subsidies.
Implementation Method 1
an adsorber that adsorbs the CO2 from the air using a sorbent
Implementation Method 2
a desorber, coupled to the adsorber, that desorbs the adsorbed CO2 from the sorbent into an output of the system
Implementation Method 3
employing a gravity-flow packed bed and a separate desorber to continuously move the sorbent through the system
Data Source
AI summary
An integrated system for adsorbing carbon dioxide (CO2) in the air is described. The system includes: an adsorber that adsorbs the CO2 from the air using a sorbent; and a desorber, coupled to the adsorber, that desorbs the adsorbed CO2 from the sorbent (e.g., in an energy-efficient manner, such as without using steam) into an output of the system. In contrast with other approaches, the system may continuously move the sorbent, as an ensemble, through the system. Thus, the system may concurrently (and continuously) perform adsorption and desorption. Moreover, the sorbent may include a cost-effective and robust free-standing bulk solid. This may allow the sorbent to be used in multiple cycles or transits through the system. Furthermore, after the multiple cycles, the sorbent may be replaced while the system is operating, and the used sorbent may be recycled for subsequent reuse in the system.