Influence of droplet mutual interaction on carbon dioxide capture process in sprays

Sprays are an important tool for carbon dioxide capture through absorption. To figure out CO₂ capture processes in sprays, the gas absorbed by a single droplet under droplet mutual interaction is investigated. In the study, the number density of droplet is in the range of 10³-10⁶cm^-3. By conceiving a bubble as the influence distance of the droplet-droplet interaction, the predictions indicate that the mutual interaction plays an important role on the absorption process and uptake amount of CO₂ when the number density is as high as 10⁶cm^-3 with droplet radius of 30μm. Specifically, the absorption period and CO₂ uptake amount of a droplet are reduced by 7% and 10%, respectively, so that the absorption rate is decreased compared to the droplet without interaction. Though the droplet mutual interaction abates the CO₂ uptake amount of a single droplet, a higher number density is conducive to the total uptake amount of CO₂ from the gas phase to the liquid phase. With the number density of 10⁶cm^-3 and increasing the droplet radius from 10 to 50μm, CO₂ capture from the gas phase to the liquid phase is intensified from 0.35% to 47.8%, even though the droplet-droplet interaction lessens the CO₂ uptake amount of a single droplet by a factor of 48%. In conclusion, a dense spray with larger droplet radii enhances the droplet-droplet interaction and thereby reduces CO₂ capture capacity of single droplets; but more solute can be removed from the gas phase.