PhD eksamen for Anders Westh Kjellow : 29. september 2010 - 29. september 2010
(Lecture Hall 1-01, Bülowsvej 17, Ground Floor, 1870 Frederiksberg C)
Ph.D. Defendant:
Cand. Silv. Anders Westh Kjellow
Time and Place:
Wednesday 29 September 2010 at 13:00 p.m. in Lecture Hall 1-01, Bülowsvej 17, Ground Floor, 1870 Frederiksberg C
Summary:
The service life of wood products is often prolonged by impregnation with biocides. A novel approach to wood impregnation involves replacing the liquid carrier with supercritical carbon dioxide. In this work, aspects of supercritical wood impregnation were addressed. The permeability of wood to both super- and subcritical CO2 was measured and found to be higher at supercritical conditions. This might be caused by the torus of aspirated bordered pits being permeable to supercritical carbon dioxide but impermeable to gas phase (subcritical) CO2. Ratios were measured of the partitioning of selected organic biocides between supercritical carbon dioxide and wood. The ratios were found to be substantially in the favor of wood especially at lower CO2 density. The microdistribution of biocides deposited by supercritical carbon dioxide was examined on a cell wall level. Findings were inconclusive probably because the deposited amount of biocide was close to the detection limit of the experimental equipment. Finally, the historic scientific efforts and contributions to the field of supercritical wood impregnation were reviewed.
Principal Supervisor:
Professor Claus Felby, Danish Centre for Forest and Landscape, Faculty of Life Sciences, University of Copenhagen
Assessment Committee:
Associate Professor Lisbeth Garbrecht Thygesen, Danish Centre for Forest and Landscape, Faculty of Life Sciences, University of Copenhagen (chairman)
Associate Professor Staffan Svensson, Technical University of Denmark
Professor Gerd H. Brunner, Institut für Thermische Verfarenstechnik, Technische Universität Hamburg-Harburg, Germany