In this work a phenomenological mathematical model that describes the continuous drying process is presented. Heat and mass transfer in gas phase, solid phase and gas-solid interface were taking in account in the model. In addition, the equilibrium and interfaces conditions were evaluated using the product sorption isotherm. Model structure is a system of four couple differential equations in conjunction with five algebraicequations. The results shown that this structure is robust with respect to heat or mass transfer controlled mechanisms. Behaviors predicted were similar with other simulators results and with the behavior reported by chemical engineering texts. The proposed mathematical model is able to use in continuous drying operation design involving heat and mass transfer properties and equilibrium relationships.