Direct air capture with amino acid solvent: Operational optimization using a crossflow air-liquid contactor

Abstract

Direct air capture (DAC) is a negative emission technology for removing CO₂ from the atmosphere to maintain the CO₂ level within a reasonable range so as to address greenhouse effects. In this study, the operational optimization of lab-scale DAC has been investigated using a crossflow air-liquid contactor loaded with a three dimensionally printed Gyroid packing structure and a potassium sarcosinate solvent. The effects of various parameters, including feed air flow rate, liquid solvent flow rate, contactor geometry, and ambient temperature, are examined. The results demonstrate that the Gyroid packing design achieves comparable CO₂ capture performance to conventional packed beds but with a significantly lower pressure drop of up to 77.8%, suggesting its potential as an efficient and cost-effective solution for gas–liquid contactors in DAC. Additionally, the study explores the climate impact on CO₂ capture performance and finds that as the air temperature increases from 35 to 95°F at a fixed relative humidity of 80%, the CO₂ capture rate increased from 23.2% to 46.8% with better stability. The research highlights the importance of optimizing contactor design and operational conditions to improve the CO₂ capture rate and feasibility of DAC systems as a negative emission technology for addressing greenhouse effects.