Abstract
The degradation of beech wood during a thermal modification process in a high-pressure reactor system using steam as medium was investigated. The wood was modified at different peak temperatures (150–180 °C), peak durations (1–6 h) and maximum water vapor pressures (0.14–0.79 MPa), while wood mass loss and wood moisture content as well as soluble degradation products were analyzed. Wood degradation was found to be predominantly determined by the maximum pressure, rather than the peak temperature applied. However, accumulation of degradation products, i.e., carbohydrates and furfural, in wood modified at elevated pressure had to be considered when using mass loss as a marker for wood degradation. Mass loss and mass loss rate increased with the maximum pressure until reaching saturation at mass losses above 20 %, due to the limited amount of amorphous carbohydrates within the wood. Several factors have been discussed with regard to their impact on accelerated degradation reactions at elevated water vapor pressure, such as a better heat transfer in a compressed gas atmosphere, reduced evaporative cooling, the accumulation of organic acids as well as the presence of water in the wood during the process. However, none of these individual factors were completely consistent with the observed mass loss progression, which leads to the conclusion that the impact of elevated water vapor pressure, rather, is a combination of several factors that apply simultaneously. The application of elevated pressure might enable an effective process technique to generate sufficient wood degradation to upgrade dimensional stability and biological durability of wood at a low temperature range.
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References
Alen R, Kotilainen R, Zaman A (2002) Thermochemical behavior of Norway spruce (Picea abies) at 180–225 °C. Wood Sci Technol 36(2):163–171
Altgen M, Ala-Viikari J, Hukka A, Tetri T, Militz H (2014) Impact of elevated steam pressure during the thermal modification of Scots pine and Norway spruce. In: COST Action FP0904 workshop, Skelleftea, Sweden
Borrega M, Kärenlampi P (2008) Effect of relative humidity on thermal degradation of Norway spruce (Picea abies) wood. J Wood Sci 54(4):323–328
Burmester A (1973) Einfluß einer Wärme-Druck-Behandlung halbtrockenen Holzes auf seine Formbeständigkeit (Effect of heat-pressure-treatments of semi-dry wood on its dimensional stability) (In German). Holz Roh Werkst 31(6):237–243
Burmester A (1975) Zur Dimensionsstabilisierung von Holz. (The dimensional stabilization of wood) (In German). Holz Roh Werkst 33(9):333–335
Candelier K, Dumarçay S, Pétrissans A, Desharnais L, Gérardin P, Pétrissans M (2013) Comparison of chemical composition and decay durability of heat treated wood cured under different inert atmospheres: nitrogen or vacuum. Polym Degrad Stabil 98(2):677–681
Chow SZ, Pickles KJ (1971) Thermal softening and degradation of wood and bark. Wood Fiber Sci 3(3):166–178
Demirbaş A (2000) Mechanisms of liquefaction and pyrolysis reactions of biomass. Energy Convers Manag 41(6):633–646
Ding T, Gu LB, Liu X (2011) Influcence of steam pressure on chemical changes of heat-treated mongolian pine wood. BioResources 6(2):1880–1889
DuBois M, Gilles KA, Hamilton JK, Rebers PA, Smith F (1956) Colorimetric Method for Determination of Sugars and Related Substances. Anal Chem 28(3):350–356
Esteves BM, Pereira HM (2009) Wood modification by heat treatment: a review. BioResources 4(1):370–404
Fengel D, Wegener G (1984) Wood: chemistry, ultrastructure, reactions. Walter de Gruyter, Berlin, p 613
Garrote G, Domínguez H, Parajó JC (1999) Hydrothermal processing of lignocellulosic materials. Holz Roh Werkst 57(3):191–202
Garrote G, Domínguez H, Parajó JC (2001) Study on the deacetylation of hemicelluloses during the hydrothermal processing of Eucalyptus wood. Holz Roh Werkst 59(1–2):53–59
Giebeler E (1983) Dimensional stabilization of wood by moisture-heat-pressure treatment. Holz Roh Werkst 41(3):87–94
Hill CAS (2006) Wood modification: Chemical, thermal and other processes. Wiley, Chichester, p 239
Hofmann T, Wetzig M, Rétfalvi T, Sieverts T, Bergemann H, Niemz P (2013) Heat-treatment with the vacuum-press dewatering method: chemical properties of the manufactured wood and the condensation water. Eur J Wood Prod 71(1):121–127
Ibbett R, Gaddipati S, Davies S, Hill S, Tucker G (2011) The mechanisms of hydrothermal deconstruction of lignocellulose: new insights from thermal-analytical and complementary studies. Bioresoruce Technol 102(19):9272–9278
Ishikawa A, Kuroda N, Kato A (2004) In situ measurement of wood moisture content in high-temperature steam. J Wood Sci 50(1):7–14
Kamdem DP, Pizzi A, Jermannaud A (2002) Durability of heat-treated wood. Eur J Wood Prod 60(1):1–6
Karlsson O, Torniainen P, Dagbro O, Granlund K, Moren T (2012) Presence of water-soluble compounds in thermally modified wood: carbohydrates and furfurals. BioResources 7(3):3679–3689
Kol HŞ, Sefil Y (2011) The thermal conductivity of fir and beech wood heat treated at 170, 180, 190, 200, and 212 °C. J Appl Polym Sci 121(4):2473–2480
Kotilainen R (2000) Chemical changes in wood during heating at 150–160 °C. PhD thesis, University of Jyväskylä, Finland
Kubojima Y, Okano T, Ohta M (2000) Bending strength and toughness of heat-treated wood. J Wood Sci 46(1):8–15
Kubojima Y, Suzuki Y, Tonosaki M, Ishikawa A (2003) Moisture content of green wood in high temperature water vapor. Holzforschung 57(6):634–638
Lenth CA, Kamke FA (2001) Equilibrium moisture content of wood in high-temperature pressurized environments. Wood Fiber Sci 33(1):104–118
Li J, Henriksson G, Gellerstedt G (2007) Lignin depolymerization/repolymerization and its critical role for delignification of aspen wood by steam explosion. Bioresource Technol 98(16):3061–3068
Metsa-Kortelainen S, Antikainen T, Viitaniemi P (2006) The water absorption of sapwood and heartwood of Scots pine and Norway spruce heat-treated at 170, 190, 210 and 230 °C. Holz Roh Werkst 64(3):192–197
Militz H, Altgen M (2014) Processes and properties of thermally modified wood manufactured in Europe. In: Schultz TP, Goodell B, Nicholas DD (eds) Deterioration and protection of sustainable biomaterials, vol 1158. ACS Symposium Series, vol 1158. American Chemical Society, pp 269–285
Mitchell PH (1988) Irreversible property changes of small Loblolly-pine specimens heated in air, nitrogen, or oxygen. Wood Fiber Sci 20(3):320–335
Nuopponen M, Vuorinen T, Jämsä S, Viitaniemi P (2005) Thermal Modifications in Softwood Studied by FT-IR and UV Resonance Raman Spectroscopies. J Wood Chem Technol 24(1):13–26
Obataya E, Higashihara T, Tomita B (2002) Hygroscopicity of heat-treated wood III. Effect of steaming on the hygroscopicity of wood. Mokuzai Gakkaishi 48(5):348–355
Popper R, Niemz P, Eberle G (2005) Investigations on the sorption and swelling properties of thermally treated wood. Holz Roh Werkst 63(2):135–148
Rautkari L, Hill CAS (2014) Effect of initial moisture content on the anti-swelling efficiency of thermally modified Scots pine sapwood treated in a high-pressure reactor under saturated steam. Holzforschung 68(3):323–326
Seborg M, Tarkow H, Stamm AJ (1953) Effect of heat upon the dimensional stabilization of wood. J For Prod Res Soc 3(3):59–67
Sivonen H, Maunu SL, Sundholm F, Jamsa S, Viitaniemi P (2002) Magnetic resonance studies of thermally modified wood. Holzforschung 56(6):648–654
Stamm AJ (1956) Thermal degradation of wood and cellulose. Ind Eng Chem 48(3):413–417
Stamm AJ, Burr HK, Kline AA (1946) Staybwood—heat-stabilized wood. Ind Eng Chem 38(6):630–634
Sundqvist B, Karlsson O, Westermark U (2006) Determination of formic-acid and acetic acid concentrations formed during hydrothermal treatment of birch wood and its relation to colour, strength and hardness. Wood Sci Technol 40(7):549–561
Tjeerdsma BF, Militz H (2005) Chemical changes in hydrothermal treated wood: FTIR analysis of combined hydrothermal and dry heat-treated wood. Holz Roh Werkst 63(2):102–111
Tjeerdsma BF, Boonstra M, Pizzi A, Tekely P, Militz H (1998) Characterisation of thermally modified wood: molecular reasons for wood performance improvement. Holz Roh Werkst 56(3):149–153
Torniainen P, Dagbro O, Moren T (2011) Thermal modification of birch using saturated and superheated steam. Proceedings of the 7th meeting of the Nordic-Baltic Network in Wodd. Mat Sci Eng (WSE), Oslo, Norway
Welzbacher C (2010) TMT-interlab-test to establish suitable quality control techniques—structure and first results. The International Research Group on Wood Protection. Doc.-No. IRG/WP 10-40503, Biarritz, France
Welzbacher C, Brischke C, Rapp A (2007) Influence of treatment temperature and duration on selected biological, mechanical, physical and optical properties of thermally modified timber. Wood Mater Sci Eng 2(2):66–76
Wikberg H, Maunu S (2004) Characterisation of thermally modified hard- and softwoods by 13C CPMAS NMR. Carbohyd Polym 58(4):461–466
Willems W (2009) Novel economic large-scale production technology for high-quality thermally modified wood. Proceedings of the 5th European Conference on Wood Modification, Stockholm, Sweden, pp 31–35
Willems W (2014) Hydrostatic pressure and temperature dependence of wood moisture sorption isotherms. Wood Sci Technol 48(3):483–498
Willems W, Mai C, Militz H (2013) Thermal wood modification chemistry analysed using van Krevelen’s representation. Int Wood Prod J 4(3):166–171
Willems W, Altgen M, Militz H (2015) Comparison of EMC and durability of heat treated wood from high versus low water vapour pressure reactor systems. Int Wood Prod J 6(1):21–26
Zaman A, Alén R, Kotilainen R (2000) Thermal Behavior of Scots Pine (Pinus sylvestris) and Silver Birch (Betula pendula) at 200°–230°. Wood Fiber Sci 32(2):138–143
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Altgen, M., Willems, W. & Militz, H. Wood degradation affected by process conditions during thermal modification of European beech in a high-pressure reactor system. Eur. J. Wood Prod. 74, 653–662 (2016). https://doi.org/10.1007/s00107-016-1045-y
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DOI: https://doi.org/10.1007/s00107-016-1045-y