On the basis of the model for aerodynamic characteristics of a FGD spray tower, a model for mass exchange in a single spray bank scrubber was developed. The relation for mass transfer units with respect to parameters characterizing dispersed and continuous phases was determined. Predictions of the scrubber efficiency for very fast and very slow reaction rates in the slurry are presented and discussed. The influence of sulfur dioxide concentration in gas and slurry feeds on the absorption efficiency are shown. A qualitative comparison with experimental data presented in the literature was performed.