The paper describes a measuring method for the determination of material drying kinetics of quick evaporation processes in a small-scale test tunnel. Extensive studies of drying kinetics for maltodextrin were performed for different solid concentrations. Critical moisture contents as a function of initial water evaporation rate (drying rate) were determined. Results of CFD modelling shown that drying kinetics obtained from small-scale tunnel could be properly applied to scale-up spray drying process.