The volumetric liquid-phase mass transfer coefficients on sieve plate have been investigated by unsteady state desorption and average concentration method. In this method there is no need for measuring the complex mixing parameters

this method is very simple and the result is reliable. Experiments were carried out with CO2 desorption by air on a ID 142mm sieve plate. The effects of hole diameter

free area

superficial gas velocity

height of s-tat-ic liquid and physical properties of liquid on the volumetric mass transfer coefficients were studied. According to the distribution of bubble diameter

the mass transfer model for swarms of bubbles was derived to correlate the experimental results: This correlation agreed well with the experimental data.