Content (Syllabus outline)

  • Task and sense of wood drying.
  • Humidity of moist gases and moisture content of solid materials, density, enthalpy and entropy of moist gases and solid materials.
  • Thermodynamic state and changes of moist gases - heating, cooling and mixing; energy conservation, psihrometry.
  • Heat and mass balances and transfer, continuous and batch drying, energy recuperation.
  • Drying kinetics of wood, permeability (Darcy and Hagen Poiselle law, capillary tension) and diffusivity (1. And 2. Fick law, thermal diffusivity) of wood, influence of wood structure on water transfer in wood. Effect of anatomical, physical and mechanical properties of wood on drying.
  • Characteristic drying curve and drying rate, intensity of drying and critical drying point.
  • Concept of wood drying - drying defects: warp, check, discolouration, drying stresses and its determination.
  • Seasoning of wood.
  • Technical drying of wood – normal temperature convective batch wood drying – kiln drying of wood, dehumidification kiln, vacuum drying, solar drying, HF drying.
  • Measuring and controlling of drying parameters.
  • Energy consumption, heat recuperation, optimization of drying process.
  • Economic of wood drying.

Prerequisites

(a) Entry in the corresponding year of the study programme.

(b)
- Attendance at exercises and written report,
- colloquium from tutorials,
- tests.