The article describes the activities of spray dry, for which was designed a mathematical model of the drying. This model allows to identify and define the process throughout drying. The output of this model is the equation of balance. Production process of ceramic granulate was selected as subject for simulations. Simulation model is created in Matlab program – Simulink according to the equation for energy balance and parameter values from real kiln. Simulation monitors the dependency of mensural granulate moisture on absolute moisture of drying gas on the output.