An Estimation of Heating Rates in Sub-Alpine Fir Lumber

Authors

  • Liping Cai

Keywords:

Heat-treatment, heating rate, mass transfer

Abstract

The objectives of this research were to explore the effects of moisture content on heating rates in subalpine fir lumber and to develop a user-friendly computer program to predict heating times during heat-treatment. A correction factor ϵ that can adjust the mass transfer coefficient based on the change of the moisture content was determined through the experiments. When moisture content, density, lumber size, initial and target temperatures, air velocity, dry-bulb and wet-bulb temperatures of the kiln are entered, the change of temperature with time can be predicted by the program. The results from the experiments and the data of previous publications confirmed that the program can be used to estimate heating times not only for sub-alpine fir, but also for other species. The results also indicated that heating wood with higher moisture content requires more energy and longer time than that with lower moisture content.

References

Fohr, J-P., A. Chakir, and M. A. du Peuty. 1995. Vacuum drying of timber. Drying Technol. 13(8&9):1675-1693.nForintek Report. 1991. The use of heat treatment in the eradication of the pinewood nematode and its vectors in softwood lumber-Task force on pasteurization of softwood lumber.nGu, L. B., and P. Garrahan. 1984. The temperature and moisture content in lumber during preheating and drying. Wood Sci. and Technol. 18: 121-135.nHou, Z. Q., X. M. Jiang, N. Guan, and Z. Chen. 2002. Theoretical determination of moisture and heat transfer to lumber during preheating. Wood Fiber Sci. 34(2): 287-292.nKreith, F., and M. S. Bohn. 2001. Principles of heat transfer. 6th Ed. Brooks/Cole Thomson Learning. Australia, Canada, Mexico, Singapore, Spain, UK, and USA.nPordage, L. J., and T. A. G. Langrish. 1999. Simulation of the effect of air velocity in the drying of hardwood timber. Drying Technol. 17(1&2):237-255.nSiau, J. F. 1995. Wood: Influence of moisture on physical properties. Virginia Polytechnic Institute and State Univ., Blacksburg, VA. Pp. 87, 94, 145.nSimpson, W. T. 2001. Heating times for round and rectangular cross sections of wood in steam. USDA. General Technical Report FPL-GTR-130.nTremblay, C., A. Cloutier, and Y. Fortin. 2000. Experimental determination of the convective heat and mass transfer coefficients for wood drying. Wood Sci. Technol. 34: 253-276.nvan Zuylen A. 1995. Platonische lifde voor hout. Chemisch Magazine: 212-213. May.n

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Published

2007-06-05

Issue

Number 2 / April 2005

Section

Research Contributions

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