Session 28 ic2011 robinson

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Session 28 ic2011 robinson

  1. 1. ©USFS
  2. 2. Since the first utilization of timber as a structural material, man has sought to extend the service life of wood by reducing moisture sorption. • Biblical Times: Pitch • Ancient Greece: Olive oil • Roman Times: First use of petroleum treatments
  3. 3. Within the last century, petroleumproducts have dominated the wood preservation industry’s moisture resistant treatments• John Bethell (1804-1867) • Full-Cell Process • Creosote • Pentachlorophenol
  4. 4. In the context of this work, water repellency is the primary mechanism for increasing wood durabilityEuropean researchers are studying many natural water-repellent treatments • Linseed Oil • Sunflower Oil • Rapeseed Oil
  5. 5. • Enviromental Impact- life of the product within the environment• Economic Impact- cost structure of the product and end-user pricingThe wood-products industry must develop ‘environmentally sensitive’products to satisfy consumer demand and the increasing regulatory pressure
  6. 6. • Improve the moisture resistance of southern yellow pine• Impregnate southern yellow pine (pinus spp.) with wood pyrolysis oil• Determine differences between high and low pressure treatment• Determine the minimum retention levels necessary for improved moisture resistance
  7. 7. Pyrolysis is a process where cellulosic biomassis heated in an oxygen-free environment:•Traditional •Slow heat transfer, long residence time •High char and low gas production•Fast •Fast heat transfer, short residence time •Low char and high gas production •Best suited for pyrolysis oil production
  8. 8. (Princeton University)
  9. 9. Characteristics:Contains over 300 compounds •Two phased: •Hydrophobic •Phenolics •Hydrophilic •Hydroxyaldehydes •Hydroxyketones •Sugars •Carboxylic Acids
  10. 10. Wood pyrolysis oil:•Rich in hydrophobic phenolic compounds•Biocidal to wood-degrading fungi. •Fungi requires moisture: • Wood is typically impervious to fungal degradation below 30% MC •Hydrophobic/biocidal compound: • economical and environmentally sustainable treatment option
  11. 11. Pyrolysis Specifications: •Auger-style reactor •Juvenile pine- forest residue •Reaction temperatures: 400-540°C •Homogenized using methanol 50%v/v •Filtered 5x using #1 Whatman paperTreatment Specifications: •Bethell full-cell process •Dilutions: 50, 40, 30, 20, 10, 5%v/v pyrolysis oil •1hr. vacuum 1hr. pressure
  12. 12. Research Methods: Water Repellency High Pressure Soak Low-Pressure SoakImpregnation methods•High Pressure: 27” Hg Vacuum : 8.5 atm Pressure•Low Pressure: 27” Hg Vacuum : 1 atm Pressure
  13. 13. Drying Vacuum Pressure Evaporation
  14. 14. Research Methods: Water RepellencyMaterials:• Whole bio-oil• Southern Yellow Pine (1” x 1” cubes) Methods: 1. Conditioned to a stable moisture content 2. Determine specific gravity
  15. 15. With increasing pyrolysis oil concentration, the size of diameter of saturated lumens increased
  16. 16. • Pyrolysis oil was successfully impregnated into Southern Yellow Pine using either high or low pressure methods• In a vapor environment moisture resistant benefits to moisture sorption and tangential expansion plateaued at concentrations of 10%• In a soak environment, benefits were directly related to the concentration of pyrolysis oil• Leachability of the treatment from the substrate is the main drawback to this treatment option

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