Importance of Temperature, Moisture Content, and Species for the Conversion Process of Wood Residues Into Fuel Pellets
Keywords:Wood pellets, pelletizing, biofuel, compression, friction, viscosity, adhesion, extractives, densification, sawdust
AbstractIn wood pellet production, knowledge is needed about the raw material properties that affect the energy requirements for pelletizing and pellet quality. This study presents novel methods for this purpose, including analyses of influence of the raw material properties on the energy requirements in the sequence of subprocesses (compression, flow, and friction components) that constitute the pelletizing process, and the strength of the pellets. The methods were used to analyze the importance of pelletizing temperature and MC and the differences between sawdust of European beech (Fagus sylvática L) and Scots pine (Pinus sylvestris L). Results showed that increasing temperature and MC decreased the energy requirements for all components of the pelletizing process and that beech required more energy than pine in all components. Beech produced the stronger pellets; increasing temperature resulted in stronger pellets, whereas increasing MC caused weaker pellets. Also, a method to quantify the energy requirements for the combined pelletizing process is presented. The methods can be used to analyze the allocation of the energy requirements of pelletizing in the die and can be useful tools for analyzing the pelletizing properties of wood and other biomass residues.
Atack D, Tabor D (1958) The friction of wood. P Roy Soc Lond A Mat 246(1247):539 - 555.nBack EL (1987) The bonding mechanism in hardboard manufacture—Review report. Holzforschung 41(4):247 - 258.nBack EL (1991) Oxidative activation of wood surfaces for glue bonding. Forest Prod J 41(2):30 - 36.nBack EL, Jansson MB, Karlberg AT, Nilvebrant NO 2000 Effect of wood resin on paper properties. Pages 343 - 355 in EL Back and LH Allen, eds. Pitch control, wood resin and deresination. Tappi Press, Atlanta, GA.nBerthold J, Rinaudo M, Salmen L (1996) Association of water to polar groups; estimations by an adsorption model for ligno-cellulosic materials. Colloid Surface 112(2-3):117 - 129.nBodig J, Goodman JR (1973) Prediction of elastic parameters for wood. J Wood Sci 5(4):249 - 264.nBowden FP, Tabor D (1966) Friction lubrication and wear—A survey of work during last decade. Br J Appl Phys 17(12):1521 - 1544.nFengel D, Wegener G (1989) Wood chemistry ultrastructure reactions. Walter de Gruyter, Berlin, Germany. 612 pp.nGardner DJ 2006 Adhesion mechanisms of durable wood adhesive bonds. Pages 254 - 265 in LH Groom and DD Stokke, eds. Characterization of the cellulosic cell wall. Blackwell Publishing, Ames, IA.nGerhards CC (1982) Effect of moisture content and temperature on the mechanical properties of wood: An analysis of immediate effects. Wood Fiber Sci 14(1):4 - 36.nGindl M, Reiterer A, Sinn G, Stanzl-Tschegg SE (2004) Effects of surface ageing on wettability, surface chemistry, and adhesion of wood. Holz Roh Werkst 62(4):273 - 280.nGoring DAI (1963) Thermal softening of lignin, hemicellulose and cellulose. Pulp Paper-Canada 64:517 - 527.nGuan N, Thunell B, Lyth K (1983) On the friction between steel and some common Swedish wood species. Holz Roh Werkst 41(2):55 - 60.nHartley ID, Kamke FA, Peemoeller H (1992) Cluster theory for water sorption in wood. Wood Sci Technol 26(2):83 - 99.nHaygreen JG, Bowyer JL (1996) Forest products and wood science. Iowa State University Press, Ames, IA. 484 pp.nHillis WE, Rozsa AN (1978) Softening temperatures of wood. Holzforschung 32(2):68 - 73.nHolm JK, Henriksen UB, Hustad JE, Sorensen LH (2006) Toward an understanding of controlling parameters in softwood and hardwood pellets production. Energy Fuels 20(6):2686 - 2694.nHolm JK, Henriksen UB, Wand K, Hustad JE, Posselt D (2007) Experimental verification of novel pellet model using a single pelleter unit. Energy Fuels 21(4):2446 - 2449.nHse CY, Kuo MI (1988) Influence of extractives on wood gluing and finishing—A review. Forest Prod J 38(1):52 - 56.nIrvine GM (1984) The glass transitions of lignin and hemicellulose and their measurement by differential thermal-analysis. TAPPI J 67(5):118 - 121.nJosefsson P, Nilsson F, Sundstrom L, Norberg C, Lie E, Jansson MB, Henriksson G (2006) Controlled seasoning of Scots pine chips using an albino strain of Ophiostoma. Ind Eng Chem Res 45(7):2374 - 2380.nKelley SS, Rials TG, Glasser WG (1987) Relaxation behavior of the amorphous components of wood. J Mater Sci 22(2):617 - 624.nKollmann FFP (1968) Mechanics and rheology of wood. Pages 292 - 420 in FPP Kollmann and WA Côté, eds. Principles of wood science and technology. Springer-Verlag, Berlin, Heidelberg, Germany.nLeaver RH (2000) Wood pellet fuel and the residential market. In Proc The Ninth Biennial Bioenergy Conference, Bioenergy 2000—Moving the technology into the marketplace, 1 - 2 Oct. 2000, Buffalo, NY.nLemoine TJ, McMillin CW, Manwiller FG (1970) Wood variables affecting the friction coefficient of spruce pine on steel. Wood Sci 2(3):144 - 148.nLjungblom L (2007) The pellets map 2007. Bioenerg Inter 29(6):9 - 23.nMatsunaga M, Obataya E, Minato K, Nakatsubo F (2000) Working mechanism of adsorbed water on the vibrational properties of wood impregnated with extractives of pernambuco (Guilandina echinata Spreng.). J Wood Sci 46(2):122 - 129.nMcKenzie WM, Karpovich H (1968) Frictional behaviour of wood. Wood Sci Technol 2(2):138 - 152.nMcMillin CW, Lemoine TJ, Manwiller FG (1970) Friction coefficient of oven-dry spruce pine on steel, as related to temperature and wood properties. Wood Fiber Sci 2(1):6 - 11.nNielsen NPK (2009) Importance of raw material properties in wood pellet production. Industrial PhD thesis, University of Copenhagen, Faculty of Life Sciences, Copenhagen, Denmark.nNielsen NPK, Gardner DJ, Felby C (2009a) Effect of extractives and storage on the pelletizing process of sawdust. Fuel (in press).nNielsen NPK, Holm JK, Felby C (2009b) Effect of fiber orientation on compressional and frictional properties of sawdust particles for fuel pellet production. Energy Fuels 23(6):3211 - 3216.nNielsen NPK, Nørgaard L, Strobel BW, Felby C (2009c) Effect of storage on extractives from particle surfaces of softwood and hardwood raw materials for wood pellets. Eur J Wood Prod 67(1):19 - 26.nNussbaum RM, Sterley M (2002) The effect of wood extractive content on glue adhesion and surface wettability of wood. Wood Fiber Sci 34(1):57 - 71.nSchneider MH (1980) Hygroscopicity of wood impregnated with linseed oil. Wood Sci Technol 14(2):107 - 114.nStehr M, Johansson I (2000) Weak boundary layers on wood surfaces. J Adhes Sci Technol 14(10):1211 - 1224.nVinterbäck J (2008) Internationell pelletsmarknadsutveckling. Presentation at SVEBIO Pellets 08, 30 - 31 Jan 2008, Sundsvall, Sweden.nZule J, Moze A (2003) GC analysis of extractive compounds in beech wood. J Sep Sci 26(14):1292 - 1294.n
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