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Computational Analysis of Heat and Mass Transfer During Torrefaction of Softwood Timber: a Dimensionless Analysis

S. Kadem(1*), A. Lachemet(2), R. Younsi(3)

(1) Chemical Engineering Institute, University of Sciences and Technology (USTHB), Algeria
(2) Chemical Engineering Institute, University of Sciences and Technology (USTHB), Algeria
(3) Department of Applied Sciences, University of Quebec at Chicoutimi, Canada
(*) Corresponding author


DOI: https://doi.org/10.15866/irea.v6i3.15689

Abstract


A 2D, unsteady-state mathematical model was used to simulate the behaviour of wood torrefaction. The model is based on Luikov’s approach and solves a set of coupled heat and mass transfer equations. The model equations are solved numerically for the temperature and moisture content histories under different treatment conditions. A parametric study was carried out over the range of 0.05 < Lu < 1, 0.01< Ko < 2, where Lu and Ko are the Luikov and Kossovitch numbers respectively. Profiles of moisture content and temperature have been predicted as a function of time and the governing parameters. It is shown that the governing dimensionless parameters have a considerable influence on the kinetics of the heat and moisture transfer.
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Keywords


Heat and Moisture Transfer; Capillary-Porous Media; Luikov’s Equations; Numerical Modelling; Validation

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References


ThermoWood Handbook, Finnish Thermowood Association, 2003, http://www.thermowood.fi/data.php/200312/795460200312311156_tw_handbook.pdf

J.L. Shi, D. Kocaefe, T. Amburgey, J. Zhang, A comparative study on brown- rot fungus decay and subterranean termite resistance of thermally-modified and ACQ-C- treated wood, sous presse, Holz als Roh- und Werkstoff 65(5) (2007) 353-358.

I. Momohara, W. Ohmura, H. Kato & Y. Kubojima Effect of High-Temperature Treatment on Wood Durability against the Brown-rot Fungus, Fomitopsis palustris, and the Termite Coptotermes formosanus, 8th International IUFRO Wood Drying Conference 2003.

J.L. Shi, D. Kocaefe, T. Amburgey, J. Zhang, Mechanical behaviour of Québec wood species heat-treated using ThermoWood Process”, Holz als Roh- und Werkstoff, 65(4) (2007) 255-259.

S. Poncsak, S. Q. Shi, D. Kocaefe, G. Miller, Impact of the thermal treatment on the adhesion between different wood Species and Adhesives, Journal of Adhesion Science and Technology, 21(8) 745-754.

S. Poncsak, D. Kocaefe, D., Bouazara, M., Pichette, A., Effect of high temperature treatment on the mechanical properties of birch, Wood Science and Technology, 40 (2006) 647-668.

A.O. Rapp, Review on heat treatment of wood, proceedings of seminar held on Antibes, France, 9 February 2001.

P. Perre, I. W. Turner, The use of numerical simulation as a cognitive tool for studying the microwave drying of softwood in an over-sized waveguide, Wood Science and Technology 33 (1999) 445-46.

S. Pang, T. A. G. Langrish, R.B. Keey, Moisture movement in softwood timber at elevated temperatures, Drying Technology 12(8) (1994) 1897-1914.

S. Pang, Relative importance of vapour diffusion and convective flow in modelling of softwood drying, Drying Technology 16(1&2) (1998) 271-281.

C. Fhyr, A. Rasmuson, Some aspects of the modelling of wood chips drying in superheated steam, Int. J. of Heat and Mass Transfer 40(12) (1997) 2825-2842.

A. Johanson, C. Fhyr, A. Rasmuson, High temperature convective drying of wood chips with air and superheated steam, Int. J. of Heat and Mass Transfer 40 (12) (1997) 2843-2858.

A.V. Luikov, Systems of differential equations of heat and mass transfer in capillary-porous bodies, Int. J. of Heat and Mass Transfer 8 (1975) 1-14.

A V. Luikov, Heat and Mass Transfer (Moscow: Mir, 1980).

S. Whitaker, Simultaneous heat, mass and momentum transfer in porous media: a theory of drying, Advances in Heat Transfer 13 (1977) 119–203.

H. R. Thomas, K. Morgan, R.W. Lewis, A fully nonlinear analysis of heat and mass transfer problems in porous media, International Journal of Numerical Methods in Engineering 15 (1980)1381-1393.

J. Irudayaraj, K. Haghighi, R.L. Stroshine, Non-linear finite element analysis of coupled heat and mass transfer problems with application to timber drying, Drying Technology 8(4) (1990) 731-749.

J.Y. Liu, S. Cheng, Solution of Luikov equations of heat and mass transfer in capillary porous bodies, Int. J of Heat and Mass Transfer 34 (7) (1991) 1747-1754.

A. G. Malan, R.W. Lewis, Modelling coupled heat and mass transfer in drying non-hygroscopic capillary particulate materials, Communications in Numerical Methods in Engineering 19 (2003) 669-677.

H. R. Thomas, R. W. Lewis and K. Morgan, An application of the finite element method to the drying of timber, Wood Fiber 11(4) (1980) 237-243.

R. Younsi, D. Kocaefe, S. Poncsak & Y. Kocaefe, Transient multiphase model for the high temperature treatment of wood, American Institute of Chemical Engineering, 52 (7) (2006) 2340-2349.

L.B. Dantas, H.R.B. Orlande and R.M. Cotta, An inverse problem of parameter estimation for heat and mass transfer in capillary porous media, International Journal of Heat and Mass Transfer 46 (2003) 1587–1598.

Comsol AB. , Femlab Version 2.0, Reference Manual, (2000).

The Mathworks Inc. MatLab Manual, Version 5.3, (1998).

R. Keylwerth, The variation of the temperature of wood during the drying of veneers and sawn wood, Holz Roh Werkstoff, 10(3) (1952) 87-91.


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