Our paper is devoted to a general approach for spray tower design. From a macroscopic point of view, this model includes the presence of a continuous gas phase, the nature of the spray nozzle, the dispersion of the droplets as well as the apparition of a film along the column wall. From a microscopic point of view, it includes the simultaneous heat and mass transfer between the various phases. The model is described by an algebro differential set of equations. This DAE system with boundary conditions at each extremity is solved by decoupling the two kinds of equations. The numerical results of our model are compared with experimental values obtained on a pilot plant. The experiments concern the absorption of a mixture of alcohols, ketones and aldehydes in air by water, and confirm the validity between our theorical approach and experimentation.