(125g) Dynamics of Absorption of CO2 into Sprayed Solvents

Low gas phase pressure drop, less susceptibility to corrosion due to the absence of internals, and greater tolerance to the use of precipitating solvents are some of the favorable attributes associated with spray columns, particularly with regard to CO₂ absorption. Specifically, there is currently a need for robust spray absorption data for the CO₂-MEA system, especially regarding droplet size data for this system. Droplet size measurements are particularly critical to ascertain the surface area available for absorption. This presentation discusses absorption rates in terms of overall mass transfer coefficients, drop size data, and planar surface area for the CO₂-MEA system quantified in a 0.2 m ID, lab-scale column. Phase Doppler Interferometry (PDI) is used to characterize the drop size distributions. The effects of L/G ratio, inlet loading, MEA concentration, and gas-liquid contact height on the performance of a full-cone nozzle are elucidated. The dropsize data and surface area quantification indicate that the free MEA content dominates spray absorption. This work provides insight about spray absorption, especially with regard to CO₂ and amine systems.