INTRODUCTIONS Team of Researchers THERMALLY MODIFIED WOODS Faculty of Forestry INTRODUCTIONS INTRODUCTIONS Definitions Chemical Modified Wood Wood modification involves the action of a chemical, biological or physical agent upon the material, resulting in a desired property enhancement during the service life of the modified wood. To modify wood, four main types of processes can be implemented: (1) chemical treatments; (2) thermo-hydro (TH) and thermo-hydro-mechanical (THM) treatments; (3) treatments based on biological processes; and (4) physical treatment with the use of electromagnetic irradiation or plasma. INTRODUCTIONS INTRODUCTIONS Thermally modified wood is wood that has been modified by a controlled pyrolysis process of wood being heated (> 180°C) in absence of oxygen inducing some chemical changes to the chemical structure of cell wall components (lignin, cellulose and hemicellulose) in the wood in order to increase its durability. “Thermal modification processes can be applied to a wide range of wood species, but they need to be optimized for each species” INTRODUCTIONS INTRODUCTIONS Thermally Modified Wood There are 5 different thermal modification processes: Thermowood (or Premium wood) in Finland, Retification process (Retiwood, New Option Wood) and Les Bois Perdure in France, Plato process in Netherlands, Oil-heat treatment in Germany (OHT-Process) Process App. Initial Temperature(‡) Pressure Process Trademarks duration Atmosphere Comments Year MC (%) (°C) (MPa) (h) INTRODUCTIONS FWD 1970 - 10-30 120-180 ≈15 0.5-0.6 Steam Closed system Thermally Modified Wood Plato 1980 PlatoWood® 14-18 150-180/ 4-5/ Super Saturated steam/ A four- stage 170-190 70-120 atmospheric heated air process up to 2 weeks pressure The different technologies of wood modification have been (partly) known for a long time, but in the past there was no economic or ThermoWood 1990 ThermoWood® 10 to 130/ 30-70 Atmospheric Steam Continuous green 185-215/ steam-flow 80-90 through the wood environmental urgency to develop these technologies. More under processing that removes recently there has been growing environmental and legislative Le Bois Perdure 1990 Perdure® green 200-230 12-36 Atmospheric Steam The process involves drying pressure on the use of biocides and traditional biocide based wood and heating the wood in steam. preservatives, that has created new opportunities for wood Retification 1997 Retiwood®, Bois ≈12 160-240 8-24 - Nitrogen or other The nitrogen Rétifié®, Réti®, gas atmosphere modification. Retibois®, guarantees a Retitech®, Retifier® maximum oxygen content of 2% OHT 2000 OHT® 10 to 180-220 24-36 - Vegetable oils Closed system green TERMOVUOTO 2010 VacWood® 0% (at the 160-220 up to 25 Vacuum Vacuum Closed system, (thermo-vacuum TVT 150-350 (1000) initial low- treated [TVT] phase) mbar temperature wood) drying from initial MC in the TV INTRODUCTIONS INTRODUCTIONS The main disadvantage is that the strength is decreased as a result of the high temperatures. In general the bending strength is The main disadvantage is that the strength is decreased as a result reduced up to 30% with more reduction at higher temperatures. of the high temperatures. In general the bending strength is reduced up to 30% with more reduction at higher temperatures. INTRODUCTIONS INTRODUCTIONS INTRODUCTIONS INTRODUCTIONS INTRODUCTIONS INTRODUCTIONS Thermally modified timber is suitable for various uses, mainly in which it is exposed to weather and humidity variations Moisture Contents above ground, e.g., for outside use in cladding, terraces, decking, garden furniture, saunas, and windows, but it is also suitable for interior use, such as kitchen furniture, flooring, decorative panels, and stairs. However, its properties and low strength do not allow it to be used in timber structures. INTRODUCTIONS PILOT PLANT HEAT TREATMENT PROCESS HEAT TREATMENT PROCESS HEAT TREATMENT PROCESS PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT PILOT PLANT NEXT STEPS THANK YOU.