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60th Anniversary 1947~2007 Kangwon National University Investigation of transformation characteristics from wood to charcoal at elevated temperature Sung-Min Kwon Nam-Hun Kim (Department of Wood Science & Engineering, College of Forest and Environmental Sciences, Kangwon National University, Korea) IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Charcoal ? Production of charcoal with a Korean traditional kiln IUFRO conference 2007 in Taiwan Charcoal is the solid residue from the pyrolysis of wood. The best materials for making charcoal in Korea are the oak woods such as Quercus variabilis, Quercus mongolica and Quercus dentata. * Characteristics of charcoal Carbon content : ca. 80 - 90% pH : ca. 8 - 9 Heating value : ca. 7000cal/g Specific surface: ca. 200-400m 2 /g

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60th Anniversary 1947~2007 Kangwon National University Utilization of charcoal IUFRO conference 2007 in Taiwan Agricultural uses Industrial uses Improvement of environmental pollution Soil improvement livestock feed additive Air purification Gases Activated carbon Pores Activated carbon adsorption Charcoal is used in variety ways.

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60th Anniversary 1947~2007 Kangwon National University Early studies Many studies were focused on the charcoal: Anatomical and physical characteristics; Beall et al. (1974), Cutter et al. (1980), Prior and Alvin (1983) Angeles (2001), Kim and Hanna (2006) Chemical characteristics; Sadakata et al. (1987), Kumar et al. (1992), Nishimiya et al. (1998), Marshall et al. (2005), Trompowsky et al. (2005) Carbon absorption; Ehrburger and Lahaye (1982), Pastor-Villegas et al. (2007), Sakurovs et al. (2007), Bornemann et al. (2007) IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Major Questions WoodCharcoal What happen? IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Carbonization process Charring temperature (C) [Ishihara S. Journal of Japan Wood Research Society. 42(8):717-723 (1996)] 0 500 1000 1500 2000 2500 3000 160 450 Thermal decomposition Charcoalization 260 800 600 1800 1600 3000 Carbonization Graphitization IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Charring temperature (C) [Prins M.J., Krzysztof K.J. and Janssen F.J.J.G., J. Anal. Appl. Pyrolysis. 77:28-34 (2006).] 0 100 200 300 400 500 Water evaporation Generating gases (CO, H, CH 4 ) Hemicellulose decomposition 225 325 250 500 Lignin decomposition 305 375 Cellulose decomposition IUFRO conference 2007 in Taiwan Decomposition of wood components

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60th Anniversary 1947~2007 Kangwon National University Objective of this study Up to now, the transition characteristic from wood to charcoal has not been clearly understood. Clarifying the transition characteristics from wood to charcoal during carbonization process. IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Experimental We focused on : Changes ofChanges of - volumetric shrinkage - volumetric shrinkage - weight loss - weight loss - vessel diameter - vessel diameter - pH - pH - cell wall morphology - cell wall morphology - crystal structure - crystal structure IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Material and Methods Species Quercus variabilis DBH* (cm) 20.3 Age 41 Green Moisture Content (%) 63.5 SapwoodHeartwood Green density (Wg/Vg) (g/cm 3 ) SapwoodHeartwood 1.07 Locality Chunchon Korea 59.51.11 *Diameter at Breast Height Table 1. Characteristics of sample tree Sample tree Latitude 3788N Longitude 12772E IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Specimens for carbonization The electric furnace used for carbonization. (HT 16/16; Supertherm, Germany) N 2 gas Chamber Sapwood Heartwood 10mm(T) 10mm(R) 20mm(L) Materials and Methods IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Carbonization using an electric furnace N 2 gas (1kg/cm 2 ) Chamber Control condition N 2 gas (1kg/cm 2 ) Chamber Heating Target temperature: 310, 320, 330, 340 and 350C Heating time to target temperature: 30 minutes N 2 gas (1kg/cm 2 ) Chamber Heating Residence time : 10 minutes Samples Cooling Sand Electric furnace Chamber Materials and Methods IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Diameter of vessel - Measuring microscope (Nicon, MM-40). - Image analyzer (IMT, i-Solution) Volumetric shrinkage and weight loss - VS (%) = V 1 - V 2 V 1 X 100 V 1 :the volume of original wood V 2 :the volume of carbonized wood Material and Methods - WL (%) = W 1 - W 2 W 1 X 100 W 1 :the weight of original wood W 2 :the weight of carbonized wood IUFRO conference 2007 in Taiwan pH - pH meter (inoLab, pH Level 2)

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60th Anniversary 1947~2007 Kangwon National University X-ray diffraction method - Sample dimensions : 1mm (R) 10mm (T) 10mm (L). - X-ray diffractometer (RIGAGU, DMAX 2100V) : Nickel-filtered CuK radiation (tube voltage: 40 kV, filament current: 40 mA) - Smooth surfaces in three-plane were obtained by cutting with a sliding microtome. - Coating : gold, about 100 thick, Ion sputtering coater (Cressington, 108). - Scanning electron microscope (JEOL JSM-5510, 15~20kV). Material and Methods Scanning electron microscopy (SEM) IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Results and Discussion Visual observation Fig. 1 Carbonized woods of Quercus variabilis at different temperatures. Control SapwoodHeartwood IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Wood 200 320C Fig. 2 Quercus variabilis wood (left) and the carbonized wood (right) at different temperatures. 200 Wood 200 310C 200 Results and Discussion IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University 340C Wood 200 Wood 330C 200 350C Wood 200 Fig. 2-1 Quercus variabilis wood(left) and the carbonized wood(right) at different temperatures. Results and Discussion IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Fig. 3 Changes of volumetric shrinkage during carbonization at different temperatures. Volumetric shrinkage Results and Discussion IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Fig. 4 Changes of weight loss during carbonization at different temperatures. Weight loss Results and Discussion IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Fig. 5 Changes of vessel diameter during carbonization at different temperatures. Sapwood Heartwood Tangential direction Radial direction Vessel diameter Results and Discussion IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Fig. 6 Changes of pH during carbonization at different temperatures. pH Results and Discussion IUFRO conference 2007 in Taiwan 0

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60th Anniversary 1947~2007 Kangwon National University SEM observation Fig. 7 Transverse surfaces of parenchyma cells of Quercus variabilis charred at different temperatures. Wood310C 320C Results and Discussion IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Fig. 7-1 Transverse surfaces of parenchyma cells of Quercus variabilis charred at different temperatures. 330C 350C 340C Results and Discussion SEM observation IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University SEM observation Fig. 8 Transverse surfaces of wood fibers of Quercus variabilis charred at different temperatures. Wood310C 320C Results and Discussion IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Fig. 8-1 Transverse surfaces of wood fibers of Quercus variabilis charred at different temperatures. 330C 350C 340C Results and Discussion SEM observation IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Fig. 9 Equatorial X-ray diffractograms of tangential surfaces of Quercus variabilis charred at different temperatures. Results and Discussion IUFRO conference 2007 in Taiwan X-ray diffraction (110) (200)

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60th Anniversary 1947~2007 Kangwon National University Summary Volume of wood samples : Volume of wood samples : - decreased with increasing the carbonization temperature - decreased with increasing the carbonization temperature - checks were developed along with radial direction - checks were developed along with radial direction Vessel diameter shrinkage : Vessel diameter shrinkage : - tangential direction > radial direction - tangential direction > radial direction Weight loss : Weight loss : - increased with increasing carbonization temperature - increased with increasing carbonization temperature - weight loss rapidly increased at the temperature ranging - weight loss rapidly increased at the temperature ranging from 330 to 340C from 330 to 340C IUFRO conference 2007 in Taiwan

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60th Anniversary 1947~2007 Kangwon National University Cell wall morphology Crystalline cellulose Carbonization temperature (C) 310320330340350 Discernible layers A glazed and amorphous appearance Detected Not detected IUFRO conference 2007 in Taiwan Summary

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60th Anniversary 1947~2007 Kangwon National University Thank you for your attention ! More information : kimnh@kangwon.ac.kr IUFRO conference 2007 in Taiwan