The fluids (liquid and gas) circulated in counter current in the column: the liquid phase was dispersed thanks to a solid cone spray nozzle located at the top of the column, whereas the gas phase was sparged at the bottom of the column. The distance between the gas and the liquid inlets was about 0.7 m. The liquid solution was stored in a tank under pressure. The liquid flow rate varied with the pressure in the storage tank but also with the spray nozzle hole diameter. Pressures from 1 to 4 bar and hole diameters of 0.8 and 1.2mm were used to provide superficial liquid velocities UL from 4.1×10−5 to 4.6×10−4 ms−1 (liquid flow rate QL from 2.64×10−3 to 2.9×10−2 m3 h−1). The gas used was compressed air in which the suitable compounds (CO2 for the interfacial area measurement, acetaldehyde for the
kLa measurement or H2S) were introduced with an automatic syringe distributor. The gas flowratewas controlled by
a rotameter and the superficial gas velocity UG varied from 9.4×10−3 to 2.8×10−2 ms−1 (gas flow rate QG from 0.6 to 1.8m3 h−1). Regarding the hydrodynamics, the two phases are considered as plug flow.