In this work we have studied the kinetic and mass-transfer behavior of spra
y-tower-loop absorbers and reactors. For this purpose, we have investigated
mass-transfer rates in the physical absorption of CO2 in water and the eff
ect on mass transfer of respectively a moderately fast reaction, such as th
e ethoxylation of nonylphenol or fatty alcohol, and an extremely fast react
ion, such as the one between CO2 and an aqueous NaOH solution. Spray nozzle
s used have been geometrically and fluid-dynamically characterized. Experim
ental results have been interpreted by considering the drops to be internal
ly stagnant or well-mixed. We have shown that an internally well-mixed drop
s model is more reliable. Moderately fast reactions, such as ethoxylation,
(Hatta number of about 1) do not affect mass transfer, while extremely fast
reactions require the introduction of an enhancement factor. We have propo
sed a semiempirical correlation for calculating this factor. Our work could
be useful for modeling and simulating spray-tower-loop absorbers and react
ors.