This study presents a mathematical description of grain pre-drying formulated as a coupled system of ordinary differential equations that captures the essential heat and mass exchange between the grain and the drying agent. The model incorporates the principal operational and material parameters, including the initial moisture content of the grain and the effective heat and mass transfer coefficients. A parametric investigation is performed to quantify the influence of these factors on dehydration kinetics and on the time required to reach technologically acceptable moisture levels. The numerical predictions are evaluated against experimental measurements and demonstrate statistically acceptable agreement, supporting the adequacy of the proposed formulation for engineering analysis. The developed framework can be employed for preliminary estimation of drying duration, sensitivity assessment of process parameters, and as a foundation for subsequent extensions that account for spatial gradients of moisture and temperature in distributed drying models.