Time (min) S o li d y ie ld (w t% ) T e m p e ra tu re ( o C ) 0 250 500 750 1000 1250 1500 1750 2000 75 80 85 90 95 100 105 50 100 150 200 250 (b) Fir
ABSTRACT
The objective of this study is to predict the treatment duration in order to reach a particular level of wood modification under industrial conditions. For that, the mass loss dynamics during the treatment are recorded and modelled. The obtained results are encouraging for a future development of a numerical tool able to conduct the heat treatment of wood in industry. Two different wood species, a hardwood: poplar (Populus nigra) and a softwood: fir (Picea abies), were used. The heat treatment was conducted at 200-230 °C for 1000 min under low air pressure (200 hPa) with less than 5% oxygen content. 1000 min duration was examined to obtain kinetic profiles required for the modelling. A two-step kinetic model is adopted to predict the mass loss dynamics of poplar and fir. The kinetic parameters are calculated from experimental data by curve-fitting. A good agreement between modelled and experimental data is achieved for the two species.
EXPERIMENTAL PROGRESS
ACKNOWLEDGEMENTS
The authors gratefully acknowledge for the financial support (program ANR-11-LABEX-0002-01, Lab of Excellence ARBRE).
SUMMARY
Wood thermal modification under industrial conditions are examined in this study. The mass loss of poplar is higher than fir. The difference of thermal sensitivity between poplar and fir is due to the hemicelluloses composition of hardwood and softwood. In addition, the kinetic parameters are calculated from experimental data by curve-fitting.
MASS LOSS DYNAMICS
Keywords: hardwood and softwood, kinetic model, thermal degradation, wood heat treatment.
Prediction of mass loss dynamics during wood thermal modification
under industrial conditions
1 Laboratoire d’Etudes et de Recherches sur le Matériau Bois, EA4370, Université de Lorraine USC INRA, IUT
Epinal - Hubert Curien, Epinal Cedex 88010, France
2 Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan
3 French Agriculture Research Centre for International Development (CIRAD), Montpellier 34398, France
E-mail of the corresponding author: bo-jhih.lin@univ-lorraine.fr
- Dimensions of wood samples: (W 170, L 600, H 22 mm)
- Drying temperature: 103°C
Sampling and drying
Heat treatment of wood
Two-step kinetic model
- Pressure: 200 hPa. - Duration: 1000 min.
- Treatment temperature: 200-230°C - Calculation of kinetic parameters. - Prediction of mass loss.
0 2.5 5 7.5 10 12.5 15 17.5 20 M a s s los s (w t% ) 0 250 500 750 1000 1250 1500 1750 Time (min ) 200 210 220 230 Temp erature (o C) 16.00 15.04 14.07 13.11 12.14 11.18 10.21 9.25 8.29 7.32 6.36 5.39 4.43 3.46 2.50 Mass loss (wt%) 0 2.5 5 7.5 10 12.5 15 17.5 20 M a s s los s (w t% ) 0 250 500 750 1000 1250 1500 1750 Time (min ) 200 210 220 230 Temp erature (o C) 16.00 15.04 14.07 13.11 12.14 11.18 10.21 9.25 8.29 7.32 6.36 5.39 4.43 3.46 2.50 Mass loss (wt%) Time (min) S o li d y ie ld (w t% ) T e m p e ra tu re ( o C ) 0 250 500 750 1000 1250 1500 1750 2000 75 80 85 90 95 100 105 50 100 150 200 250 (a) Poplar 230 oC 200 oC 210 oC 220 oC
PREDICTION OF MASS LOSS
Bo-Jhih Lin
1, Edgar Silveira
1, Baptiste Colin
1, Anélie Pétrissans
1, Wei-Hsin Chen
2, Patrick Rousset
3, Mathieu Pétrissans
1Scheme of two-step kinetics
Poplar
Fir
