On the feasibility of acceleration-based separation strategies for CO₂ capture

Concerns surrounding climate change have motivated significant effort towards low-cost CO₂ capture.  To date, many creative CO₂ capture strategies have been proposed, including semipermeable membranes, various catalytic and chemical processes, and even cryogenic cooling. This study evaluates the feasibility of a fluid mechanic, acceleration-based separation process which would leverage the relatively high molecular weight of CO₂ compared to other combustion product gases, such as N₂, O₂, and H₂O. In this approach, the entropy of mixing enforces a thermodynamic limit on the separation process for a given acceleration field. It is shown that extremely high accelerations (greater than 10⁶ m/s²) are required to achieve meaningful CO₂ purity levels at standard conditions. As such, achieving useful levels of separation in a steady flowing device such as a spinning drum seems impractical. Strategies to potentially improve the feasibility of acceleration-based CO₂ separation are also discussed.