Abstract
The temperature and moisture profiles during thermal modification of beech (Fagus sylvatica L.) and spruce (Picea abies L. Karst.) wood have been investigated. Specimens with dimensions of 80×80×200 mm3 were heat treated based on ThermoWood technology. Heat transfer was continuously measured by several thermocouples placed into various positions of the samples. In the course of the treatment, samples were removed from the chamber at different times, and their moisture content (MC) was measured by the so-called slicing technique. The complete data of heat and moisture movement during the heat treatment process are presented. Significant temperature gradients occur in the initial and modification stages of the process. In the latter, the chamber temperature was 200°C for 3 h, but exothermic reaction increased the sample temperatures to 240°C (beech) and 215°C (spruce). Thermodiffusion (Soret effect) at the beginning of the process was observed. Therefore, the MC under surfaces (in transverse and in longitudinal direction) was increasing ∼0.5%–3% for 5 h. The results provide a better insight into details of thermal modification of wood.
The authors are grateful to reviewers, who helped in clarifying this article. The authors are also grateful to KATRES Company, especially to Karel Slimáček, for the assistance during experiments. This work was funded by the European Social Fund and the state budget of the Czech Republic (project “The Establishment of an International Research Team for the Development of New Wood-Based Materials”, reg. no. CZ.1.07/2.3.00/20.0269) and by the Internal Grant Agency (IGA) of the Faculty of Forestry and Wood Technology, Mendel University in Brno (Project No. 26/2012).
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