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Taneli Väisänen: Effects of Thermally Extracted Wood Distillates on the Characteristics of Wood-Plastic Composites conversion and devolatilization take place; the maximum temperature of the process typically ranges between 200 °C and 300 °C. (Williams and Besler 1996, Klass 1998, Nachenius et al. 2013) Pyrolysis and charcoal production have a long history. Traditionally, charcoal has been produced in kilns, but modern charcoal production utilizes large retorts with capacities of 100 m 3 or even more. In addition, these systems are typically combined with refining facilities to capture the volatile products. The most common types of processes used in the industry are the Reichert retort process, the SIFIC, and the Lambiotte process. A Reichert facility typically consists of multiple retorts (up to six), and therefore, has a high rate of production. For example, the Reichert production facility operated by proFagus GmbH in Bodenfelde, Germany, has been designed to produce 30 000 tons of charcoal, 5 200 tons of acetic acid, 1 800 tons of pyroligneous spirit, and 12 000 tons of bio-oil per year. The charcoal production capacity in a traditional Lambiotte retort is 12 000 tons per year. (Dahmen et al. 2010) The decomposition of cellulose and hemicelluloses produces primarily condensable vapors and non-condensable gases. Lignin decomposes into liquids, gases, and charcoal. The decomposition or volatilization of extractives produces liquid or gas products. Minerals and ash remain solid in charcoal, and they exert a catalytic effect on the pyrolysis reactions; these compounds increase the yield of charcoal. (Williams and Besler 1996, Nachenius et al. 2013) The pyrolytic production processes require only small amounts of external energy. When the temperature is below 200 °C, the process is endothermic and it produces primarily water, formic acid, and acetic acid. At 200–270 °C, the process becomes partly exothermic. At this stage, the main products are carbon dioxide, formic acid, and acetic acid. When the temperature reaches 350–400 °C, the process reactions are highly exothermic, producing a great number of products, such as methanol, formaldehyde, and tar compounds. When 400 °C is exceeded, the reaction heat becomes weakly endothermic, 66 Dissertations in Forestry and Natural Sciences No 222
Thermal processing of wood and the process produces non-condensable gases. The energy efficiency of pyrolysis can be further optimized by recycling the heat energy present in the non-condensable gases. The moisture content of the raw material is an important factor affecting the energy efficiency of the process; if the moisture content exceeds 30%, the process will be endothermic. (Dahmen et al. 2010, Nachenius et al. 2013) 4.3 PRODUCTS OBTAINED FROM THE PROCESSES Even though the most important and commercially relevant product in the ThermoWood ® process is the thermally modified wood itself, other products are also formed during the process. The maximum temperature used in the ThermoWood ® process is 215 °C, and the reactions are carried out in the presence of steam. Hemicelluloses and extractives are decomposed at temperatures below 215 °C (Figure 9), and some minor changes occur in lignin. Therefore, the products formed in this process are primarily liquids and gases formed from these constituents. The formation of solid products, such as charcoal, is minor. The maximum temperature in slow pyrolysis, in turn, exceeds the decomposition temperatures of all wood constituents (Figure 9), and the products of slow pyrolysis can be found in the gaseous, liquid and solid phases. Gaseous products include hydrogen, methane, carbon monoxide, and carbon dioxide. The liquids include tars and oils that remain in the liquid form at room temperature. Solid products are mainly composed of charcoal, but other inert materials are also present. (Dahmen et al. 2010, Bhaskar et al. 2011, Basu 2013) 4.3.1 Charcoal Charcoal is the main product from slow pyrolysis, consisting mainly of carbon (60–90%), hydrogen, and oxygen. Charcoal production requires slow heating rate for a long duration but at a relatively low temperature (400 °C). Charcoal is used as an energy source especially in developing countries, but it has Dissertations in Forestry and Natural Sciences No 222 67
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PUBLICATIONS OF THE UNIVERSITY OF E
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Grano Oy Jyväskylä, 2016 Editors:
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ABSTRACT The use of raw materials d
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Universal Decimal Classification: 6
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Finally, I am grateful to my wife A
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TD-GC-FID/MS Thermal desorption/gas
Page 17 and 18: LIST OF ORIGINAL PUBLICATIONS This
Page 19 and 20: Contents 1 Introduction ...........
Page 21 and 22: 1 Introduction The finiteness of cr
Page 23 and 24: Introduction A new and environmenta
Page 25 and 26: 2 Wood-plastic composites By defini
Page 27 and 28: Wood-plastic composites additives u
Page 29 and 30: Wood-plastic composites Cellulose i
Page 31 and 32: Wood-plastic composites The propert
Page 33 and 34: Wood-plastic composites Figure 3. T
Page 35 and 36: Wood-plastic composites of lubrican
Page 37 and 38: Wood-plastic composites roughness a
Page 39 and 40: Wood-plastic composites Hosseinaei
Page 41 and 42: Wood-plastic composites the accessi
Page 43 and 44: Wood-plastic composites However, WP
Page 45 and 46: Wood-plastic composites A typical s
Page 47 and 48: Wood-plastic composites to fill the
Page 49: Wood-plastic composites absorption.
Page 52 and 53: Taneli Väisänen: Effects of Therm
Page 63 and 64: 4 Thermal processing of wood Therma
Page 65 and 66: Thermal processing of wood Figure 9
Page 67: Thermal processing of wood counterp
Page 71 and 72: Thermal processing of wood and Miet
Page 73 and 74: 5 Aims and significance Despite the
Page 75 and 76: 6 Materials and methods Two types o
Page 77 and 78: Materials and methods heat energy f
Page 79 and 80: Materials and methods with the untr
Page 81 and 82: Materials and methods 6.2.1 Tensile
Page 83 and 84: Materials and methods 6.3 WATER ABS
Page 85 and 86: Materials and methods The emissions
Page 87: Materials and methods where Evoc is
Page 115 and 116: 9 Summary and conclusions In the pr
Page 117 and 118: Bibliography Abdolvahaba E, Lashgar
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Bibliography Ayrilmis N, Jarusombut
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Bibliography Cernansky R. State-of-
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Bibliography polypropylene composit
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Bibliography with odor assessments
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Bibliography La Mantia FP, Morreale
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Bibliography Mohan D, Pittman CU, a
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Bibliography Rinne J, Taipale R, Ma
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Bibliography Stark NM and Rowlands
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Bibliography Yeh S and Gupta RK. Im
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