Drying kinetics of convectional drying of beechwood (Fagus sylvatica L.) was researched at common stationary drying and at adaptive kiln drying process. We used radially oriented specimens of thickness from 6 mm to 24 mm, having sawn and planed drying surface. Firstly, a series of convectional drying processes were carried out in the laboratory tunnel drier at constant drying conditions of 30 °C, at relative humidity of 85%, varying air velocity (v) from 0.6 m/s to 7.6 m/s. During the drying, moisture content (u) and water mass flow were gravimetrically determined at successive time intervals. In the second part of the research, the real water mass flow and the iteratively adaptive drying potential were used at the computer controlled convective drying. Drying rate generally increased with the air velocity and decreased with the increasing thickness of wood. Low air velocities caused also initially higher drying rate at specimens with planed surface comparing to sawn one, due to differences of the surface mass transfer coefficient. Increasing of the air velocity (v > 2.5 m/s) caused irreversible reduction of initial water mass flow and transition to the period of falling drying rate, where the internal water mass resistance predominates. Too high initial drying rate, especially at greater material thicknesses caused high initial moisture content gradient and significantly prolonged the drying process in continuation. Adaptive drying was generally faster in comparison to convective drying at constant climatic conditions. In the first drying period, at the removal of free water, the optimized drying potential was reached with the iterative variation of the air humidity and the air velocity. Combination of the air humidity and the temperature was successful to optimize the drying potential at the moisture content bellow fibre saturation, where higher internal mass transfer resistance existed.
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