Impact of various conventional drying conditions on drying rate and on moisture content gradient during early stage of beechwood drying

Pervan, Stjepan (author), Straže, Aleš (author), Gorišek, Željko (author)

An appropriate moisture transport and a control of moisture distribution are needed from the early beginning of drying process, especially at drying of high dense and less permeable hardwoods. For determination of suitable process conditions at drying of European beechwood (Fagus sylvatica L.) the unidirectional drying kinetics, with an emphasis of free water removal was researched. We used radially oriented sapwood specimens, having thickness from6 mm to 24 mm (f L = 6 mm). Series of conventional drying processes were carried out in the laboratory tunnel drier at constant climate (T = 30 <C) RH= 85%) and with varying air velocity (v) from 0.6 m/s to 7.6 m/s. During the drying, moisture content (MC), MC gradient and moisture flow were gravimetrically determined at successive time intervals. Drying rate generallyincreased with rising of air velocity and decreased with increasing thickness of wood. Relatively constant drying rate was present at the initial stage of drying of thin specimens (. 12 mm) in a short time interval, when lowair velocity was used (. 2.5 m/s). Increasing of the air velocity (> 2.5 m/s) lead to early irreversible reduction of initial moisture flow and transition to the period of significantly falling drying rate, where the internal mass resistance predominated and caused high initial moisture content gradient. The diffusion barrier was induced at too fast free water removal which controlled further drying rate and significantly prolonged the drying process in continuation.

• Language: English
• Work type: Not categorized
• Typology: 1.08 - Published Scientific Conference Contribution
• Organization: BF - Biotechnical Faculty
• Year: 2010
• Number of pages: Str. 39-47
• PID: 20.500.12556/RUL-83236
• UDC: 630*847
• COBISS.SI-ID: 1820553
• Publication date in RUL: 18.08.2016

Record is a part of a monograph

• Title: The future of quality control for wood & wood products : Proceedings of the final conference of COST Action E53: Quality control for wood & wood products 4 - 7th May 2010, Edinburgh, UK
• Editors: D. J. Ridley-Ellis, J. R. Moore
• Place of publishing: Edinburgh
• Publisher: Edinburgh Napier University, Forest Products Research Institute / Centre for Timber Engineering
• Year: 2010
• ISBN: 978-0-9566187-0-2
• COBISS.SI-ID: 1819785

Secondary language

• Language: Slovenian
• Keywords: sušenje lesa, Fagus sylvatica L., bukev