Summary
A procedure is presented to estimate the relative vapor pressure, equilibrium moisture content, average flake temperature, and average flake moisture content in a flakeboard mat during hot-pressing. This method is based on measurements of temperature and total gas pressure in the mat during hot-pressing. A heat and mass transfer model was adapted from the literature to predict the temperature and moisture content inside an individual flake. Significant moisture gradients are predicted to develop within flakes. Convective heat transfer appears to control the change of moisture content within a flake. Thermodynamic equilibrium between the gas phase and the wood component is not achieved during hot-pressing.
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Back, E. L. 1987: The bonding mechanism in hardboard manufacture. Holzforschung 41: 247–258
Benjamin, J. R.; Cornell, C. A. 1970: Probability, statistics, and decision for civil engineers. New York: McGraw Hill
Brady, D. E.; Kamke, F. A. 1988: Effects of hot-pressing parameters on resin penetration. For. Prod. J. 38: 63–68
Chow, S. Z.; Mukai, H. N. 1972: Polymerization of phenolic resin at high vapor pressure. Wood Sci. 5: 65–72
Forest Products Laboratory 1987: Wood handbook: Wood as an engineering material. Agric. Handb. 72, p. 3–11. Washington, DC: U.S. Department of Agriculture
Frantz, J. F. 1961: Fluid-to-particle heat transfer in fluidized beds. Chem. Engr. Prog. 57: 35–42
Geimer, R. L.; Mahoney, R. J.; Loehnertz, S. P.; Meyer, R. W. 1985: Influence of processinginduced damage on strength of flakes and flakeboards. FPL Res. Pap. No. 463. U.S. For. Prod. Lab., Madison, WI
Harless, P. E.; Wagner, F. G.; Short, P. H.; Seale, R. D.; Mitchell, P. H.; Ladd, D. S. 1987: A model to predict the density profile of particleboard. Wood Fiber Sci. 19: 81–92
Humphrey, P. E. 1979: Fundamental aspects of wood particleboard manufacture. Ph.D. Dissertation. Univ. of Wales, Bangor, Wales, U.K.; 158 p
Kamke, F. A.; Wilson, J. B. 1986: Computer simulation of a rotary dryer: Part II: Heat and mass transfer. AIChE J. 32: 269–275
Kamke, F. A.; Casey, L. J. 1988a: Gas pressure and temperature in the mat during flakeboard manufacture. For. Prod. J. 38: 41–43
Kamke, F. A.; Casey, L. J. 1988b: Fundamentals of flakeboard manufacture: internal mat conditions. For. Prod. J. 38: 38–44
Kayihan, F.; Johnson, J. A. 1983: Heat and moisture movement in wood composite materials during the pressing operation — a simplified model. In: Lewis, R. W.; Morgan, K.; Schrefler, B. A. (Eds.): Numerical methods in heat transfer. Vol. 2, New York: Wiley
Perry, R. H.; Chilton, C. H. 1973: Chemical engineers' handbook. 5 Ed. pp. 5–62. New York: McGraw-Hill
Resch, H.; Hoag, M. L.; Rosen, H. N. 1988: Desorption of yellow poplar in superheated steam. For. Prod. J. 38: 13–18
Simpson, W. T. 1971: Equilibrium moisture content prediction for wood. For. Prod. J. 21: 48–49
Simpson, W. T. 1973: Predicting equilibrium moisture content of wood by mathematical models. Wood Fiber 5: 41–49
Simpson, W. T.; Rosen, H. N. 1981: Equilibrium moisture content of wood at high temperatures. Wood Fiber 13: 150–158
Schajer, G. S. 1984: DRYRUN, One dimensional wood drying computer program..Solid Wood Research and Development, Weyerhaeuser Company, Tacoma, WA
Snedecor, G. W.; Cochran, W. G. 1967: Statistical methods. 6 Ed., p. 432. Ames, IA: Iowa State University Press
Stanish, M. A.; Schajer, G. S.; Kayihan, F. 1985: Mathematical models of wood drying from heat and mass transfer fundamentals. In: Toei, R.; Mujumdar, A. S. (Eds.): Drying '85. pp. 360–367. New York: Hemisphere
Strickler, M. D. 1959: Properties of Douglas-fir flakeboard. For. Prod. J. 7: 203–215
Toei, R.; Okazaki, M.; Kimura, M.; Ueda, H. 1967: Heat transfer coefficients on the super-heat-ed steam drying of porous solids. Kagaku Kogaku 5: 139–141
Treybal, R. E. 1980: Mass-transfer operations. pp. 202. New York: McGraw-Hill
Wolcott, M. P.; Kamke, F. A.; Dillard, D. A. 1989: Fundamentals of flakeboard manufacture: viscoelastic behavior of the wood component. Wood Fiber Sci. (in press)
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This work was funded by the USDA Competitive Grant Program for Forest and Rangeland Renewable Resources, Project No. 85-FSTY-9-0106 and 87-FSTY-9-0253
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Kamke, F.A., Wolcott, M.P. Fundamentals of flakeboard manufacture: wood-moisture relationships. Wood Sci.Technol. 25, 57–71 (1991). https://doi.org/10.1007/BF00195557
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DOI: https://doi.org/10.1007/BF00195557